ICRC Interpretive Guidance On The Notion of Direct Participation in Hostilities

Part II – Direct Participation in Hostilities 1
Document No. 51, ICRC, Interpretive Guidance

on the Notion of Direct Participation in Hostilities
[Source: ICRC, Interpretive Guidance on the Notion of Direct Participation in Hostilities under International
Humanitarian Law, Geneva, May 2009; available at www.icrc.org. Footnotes omitted.]
FOREWORD
The protection of civilians is one of the main goals of international humanitarian law.
Pursuant to its rules on the conduct of hostilities, the civilian population and individual
civilians enjoy general protection against the effects of hostilities. Accordingly, the law
obliges the parties to an armed conflict to distinguish, at all times, between the civilian
population and combatants and to direct operations only against military targets. It
also provides that civilians may not be the object of deliberate attack. In the same vein,
humanitarian law mandates that civilians must be humanely treated if and when they
find themselves in the hands of the enemy. This overarching norm finds expression in
many provisions of humanitarian law, including those prohibiting any form of violence
to life, as well as torture or cruel, inhuman or degrading treatment.
Unusual as it may seem today, the comprehensive protection of civilians was not
always a main focus of international humanitarian law. Its origins, at least in terms
of treaty rules, lie at a time when civilian populations were largely spared from the
direct effects of hostilities and actual fighting was carried out only by combatants. In
1864, when the First Geneva Convention was adopted, armies faced off on battlefields
with clearly drawn frontlines. It was the suffering of soldiers, often tens of thousands
of them who lay wounded or dying after a military engagement that needed to be
alleviated. Only later, when technological innovations in weaponry started causing
massive civilian suffering and casualties in war, did the protection of civilians also need
to be addressed.
Over time, and particularly after the Second World War, the law also had to regulate the
consequences of more and more frequent direct participation by civilians in hostilities.
Two situations were emblematic: first, wars of national liberation in which government
forces faced off against “irregular” armed formations fighting for the freedom of
colonized populations. In 1977 Additional Protocol I recognized that such wars could
under certain circumstances be deemed international in character. A second situation
has become prevalent and remains of great concern today: armed conflicts not of an
international character waged between government forces and organized non-State
armed groups, or between such groups, for political, economic, or other reasons.
It hardly needs to be said that these types of conflicts, in which parts of the civilian
population are effectively transformed into fighting forces, and in which civilians are
also the main victims, continue to cause untold loss of life, injury and destruction.
International humanitarian law has addressed the trend towards increased civilian
participation in hostilities by providing a basic rule, found in both Additional Protocols
to the Geneva Conventions, pursuant to which civilians benefit from protection against
direct attack “unless and for such time as they take a direct part in hostilities”. It is the
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meaning of this notion – direct participation in hostilities – that the present Interpretive
Guidance seeks to explain. In examining the notion of direct participation in hostilities
the ICRC not only had to face longstanding dilemmas that had surrounded its practical
application (e.g., can a person be a protected farmer by day and a targetable fighter
at night?), but also had to grapple with more recent trends that further underlined the
need for clarity. One such trend has been a marked shift in the conduct of hostilities
into civilian population centres, including cases of urban warfare, characterized by
an unprecedented intermingling of civilians and armed actors. Another has been the
increased outsourcing of previously traditional military functions to a range of civilian
personnel such as private contractors or civilian government employees that has made
distinguishing between those who enjoy protection from direct attack and those who
do not ever more difficult. A third, particularly worrying trend has been the failure
of persons directly participating in hostilities, whether civilians or members of armed
forces or groups, to adequately distinguish themselves from the civilian population.
The Interpretive Guidance provides a legal reading of the notion of “direct participation
in hostilities” with a view to strengthening the implementation of the principle of
distinction. In order for the prohibition of directing attacks against civilians to be
fully observed, it is necessary that the armed forces of parties to an armed conflict
– whether international and non-international – be distinguished from civilians, and
that civilians who never take a direct part in hostilities be distinguished from those
who do so on an individual, sporadic or unorganized basis only. The present text
seeks to facilitate these distinctions by providing guidance on the interpretation
of international humanitarian law relating to the notion of direct participation in
hostilities. In so doing, it examines three questions: who is considered a civilian for the
purposes of the principle of distinction, what conduct amounts to direct participation
in hostilities and what modalities govern the loss of protection against direct attack.
The responses provided and the resulting interpretations included in the Interpretive
Guidance tackle one of the most difficult, but as yet unresolved issues of international
humanitarian law. The ICRC initiated reflection on the notion of direct participation in
hostilities based both on the need to enhance the protection of civilians in practice for
humanitarian reasons and on the international mandate it has been given to work for
the better understanding and faithful application of international humanitarian law. In
this context, it is appropriate that three observations be made: First, the Interpretive
Guidance is an expression of solely the ICRC’s views. While international humanitarian
law relating to the notion of direct participation in hostilities was examined over several
years with a group of eminent legal experts, to whom the ICRC owes a huge debt
of gratitude, the positions enunciated are the ICRC’s alone. Second, while reflecting
the ICRC’s views, the Interpretive Guidance is not and cannot be a text of a legally
binding nature. Only State agreements (treaties) or State practice followed out of a
sense of legal obligation on a certain issue (custom) can produce binding law. Third,
the Guidance does not purport to change the law, but provides an interpretation of
the notion of direct participation in hostilities within existing legal parameters.
The present text interprets the notion of direct participation in hostilities for the
purposes of the conduct of hostilities only. Thus, apart from providing guidance on
when and for how long a person is considered to have lost protection from direct
attack, it does not address the consequences of direct participation in hostilities once
he or she finds him or herself in the adversary’s hands. Other rules of international
humanitarian law then govern, foremost among them being the already mentioned
principle of humane treatment.
Unfortunately, there seems to be little reason to believe that the current trend towards
increased civilian participation in hostilities will weaken over time. Today, more than
ever, it is of the utmost importance that all feasible measures be taken to prevent the
exposure of the civilian population to erroneous or arbitrary targeting based, among
other things, on reliable guidance as to how to the principle of distinction should be
implemented in the challenging and complex circumstances of contemporary warfare.
By presenting this Interpretive Guidance, the ICRC hopes to make a contribution to
ensuring that those who do not take a direct part in hostilities receive the humanitarian
protection that they are entitled to under international humanitarian law.
Dr. Jakob Kellenberger
President of the International Committee of the Red Cross
[…]
INTRODUCTION
1. Purpose and nature of the Interpretive Guidance

The purpose of the Interpretive Guidance is to provide recommendations concerning
the interpretation of international humanitarian law (IHL) as far as it relates to the
notion of direct participation in hostilities. Accordingly, the 10 recommendations
made by the Interpretive Guidance, as well as the accompanying commentary,
do not endeavour to change binding rules of customary or treaty IHL, but reflect
the ICRC’s institutional position as to how existing IHL should be interpreted in
light of the circumstances prevailing in contemporary armed conflicts.
The Interpretive Guidance draws on a variety of sources including, first and foremost,
the rules and principles of customary and treaty IHL and, where necessary, the travaux
préparatoires of treaties, international jurisprudence, military manuals, and standard
works of legal doctrine. Additionally, it draws on the wealth of materials produced in
the course of an expert process, jointly initiated by the ICRC and the TMC Asser Institute
with the aim of clarifying the notion of direct participation in hostilities under IHL. Five
informal expert meetings were conducted from 2003 to 2008 in The Hague and Geneva,
each bringing together 40 to 50 legal experts from academic, military, governmental,
and nongovernmental circles, all of whom participated in their private capacity.
The Interpretive Guidance is widely informed by the discussions held during these
expert meetings but does not necessarily reflect a unanimous view or majority
opinion of the experts. It endeavours to propose a balanced and practical solution
that takes into account the wide variety of concerns involved and, at the same time,
ensures a clear and coherent interpretation of the law consistent with the purposes
4 Document No. 51
and principles of IHL. Ultimately, the responsibility for the Interpretive Guidance
is assumed by the ICRC as a neutral and independent humanitarian organization
mandated by the international community of States to promote and work for
a better understanding of IHL. Although a legally binding interpretation of IHL
can only be formulated by a competent judicial organ or, collectively, by the States
themselves, the ICRC hopes that the comprehensive legal analysis and the careful
balance of humanitarian and military interests underlying the Interpretive Guidance
will render the resulting recommendations persuasive for States, non-State actors,
practitioners, and academics alike.
The Interpretive Guidance consists of 10 recommendations, each of which summarizes
the ICRC’s position on the interpretation of IHL on a particular legal question, and a
commentary explaining the bases of each recommendation. Throughout the text,
particularly where major divergences of opinion persisted among the experts,
footnotes refer to the passages of the expert meeting reports and background
documents where the relevant discussions were recorded. The sections and
recommendations of the Interpretive Guidance are closely interrelated and can
only be properly understood if read as a whole. Likewise, the examples offered
throughout the Interpretive Guidance are not absolute statements on the legal
qualification of a particular situation or conduct, but must be read in good faith, within
the precise context in which they are mentioned and in accordance with generally
recognized rules and principles of IHL. They can only illustrate the principles based
on which the relevant distinctions ought to be made, but cannot replace a careful
assessment of the concrete circumstances prevailing at the relevant time and place.
Lastly, it should be emphasized that the Interpretive Guidance examines the concept
of direct participation in hostilities only for the purposes of the conduct of
hostilities. Its conclusions are not intended to serve as a basis for interpreting IHL
regulating the status, rights and protections of persons outside the conduct of
hostilities, such as those deprived of their liberty. Moreover, although the Interpretive
Guidance is concerned with IHL only, its conclusions remain without prejudice to
an analysis of questions related to direct participation in hostilities under other
applicable branches of international law, such as human rights law or the law
governing the use of interstate force (jus ad bellum).
2. The issue of civilian participation in hostilities

The primary aim of IHL is to protect the victims of armed conflict and to regulate the
conduct of hostilities based on a balance between military necessity and humanity.
At the heart of IHL lies the principle of distinction between the armed forces, who
conduct the hostilities on behalf of the parties to an armed conflict, and civilians, who
are presumed not to directly participate in hostilities and must be protected against the
dangers arising from military operations. Throughout history, the civilian population
has always contributed to the general war effort of parties to armed conflicts, for
example through the production and supply of weapons, equipment, food, and
shelter, or through economic, administrative, and political support. However, such
activities typically remained distant from the battlefield and, traditionally, only a small
minority of civilians became involved in the conduct of military operations.
Recent decades have seen this pattern change significantly. A continuous shift of
the conduct of hostilities into civilian population centres has led to an increased
intermingling of civilians with armed actors and has facilitated their involvement
in activities more closely related to military operations. Even more recently, the
increased outsourcing of traditionally military functions has inserted numerous private
contractors, civilian intelligence personnel, and other civilian government employees
into the reality of modern armed conflict. Moreover, military operations have often
attained an unprecedented level of complexity, involving the coordination of a great
variety of interdependent human and technical resources in different locations.
All of these aspects of contemporary warfare have given rise to confusion and
uncertainty as to the distinction between legitimate military targets and persons
protected against direct attacks. These difficulties are aggravated where armed
actors do not distinguish themselves from the civilian population, for example during
undercover military operations or when acting as farmers by day and fighters by night.
As a result, civilians are more likely to fall victim to erroneous or arbitrary targeting,
while armed forces – unable to properly identify their adversary – run an increased
risk of being attacked by persons they cannot distinguish from the civilian population.
3. Key legal questions

This trend underlines the importance of distinguishing not only between civilians
and the armed forces, but also between civilians who do and, respectively, do not
take a direct part in hostilities. Under IHL, the concept of direct participation in
hostilities refers to conduct which, if carried out by civilians, suspends their protection
against the dangers arising from military operations. Most notably, for the duration
of their direct participation in hostilities, civilians may be directly attacked as if they
were combatants. Derived from Article 3 common to the Geneva Conventions, the
notion of taking a direct or active part in hostilities is found in many provisions of IHL.
However, despite the serious legal consequences involved, neither the Conventions
nor their Additional Protocols provide a definition of direct participation in hostilities.
This situation calls for the clarification of three questions under IHL applicable in both
international and non-international armed conflict:
• Who is considered a civilian for the purposes of the principle of distinction? The answer to
this question determines the circle of persons who are protected against direct attack
unless and for such time as they directly participate in hostilities.
[Footnote: The status, rights, and protections of persons outside the conduct of hostilities does not depend on
their qualification as civilians but on the precise personal scope of application of the provisions conferring the
relevant status, rights, and protections (e.g., Arts 4 GC III, 4 GC IV, 3 GC I-IV, 75 AP I, 4 to 6 AP II).]
• What conduct amounts to direct participation in hostilities? The answer to this question
determines the individual conduct that leads to the suspension of a civilian’s protection
against direct attack.
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• What modalities govern the loss of protection against direct attack? The answer to this
question will elucidate issues such as the duration of the loss of protection against
direct attack, the precautions and presumptions in situations of doubt, the rules
and principles governing the use of force against legitimate military targets, and the
consequences of regaining protection against direct attack.
Part 1: RECOMMENDATIONS OF THE ICRC

concerning the interpretation of international humanitarian law
relating to the notion of direct participation in hostilities
I. The concept of civilian in international armed conflict

For the purposes of the principle of distinction in international armed conflict, all
persons who are neither members of the armed forces of a party to the conflict nor
participants in a levée en masse are civilians and, therefore, entitled to protection
against direct attack unless and for such time as they take a direct part in hostilities.
II. The concept of civilian in non-international armed conflict

For the purposes of the principle of distinction in non-international armed conflict,
all persons who are not members of State armed forces or organized armed groups
of a party to the conflict are civilians and, therefore, entitled to protection against
direct attack unless and for such time as they take a direct part in hostilities. In non-
international armed conflict, organized armed groups constitute the armed forces
of a non-State party to the conflict and consist only of individuals whose continuous
function it is to take a direct part in hostilities (“continuous combat function”).
III. Private contractors and civilian employees

Private contractors and employees of a party to an armed conflict who are civilians
(see above I and II) are entitled to protection against direct attack unless and for such
time as they take a direct part in hostilities. Their activities or location may, however,
expose them to an increased risk of incidental death or injury even if they do not take
a direct part in hostilities.
IV. Direct participation in hostilities as a specific act

The notion of direct participation in hostilities refers to specific acts carried out by
individuals as part of the conduct of hostilities between parties to an armed conflict.
V. Constitutive elements of direct participation in hostilities

In order to qualify as direct participation in hostilities, a specific act must meet the
following cumulative criteria:
1. The act must be likely to adversely affect the military operations or military
capacity of a party to an armed conflict or, alternatively, to inflict death, injury, or
destruction on persons or objects protected against direct attack (threshold of

harm), and
2. There must be a direct causal link between the act and the harm likely to result
either from that act, or from a coordinated military operation of which that act
constitutes an integral part (direct causation), and
3. The act must be specifically designed to directly cause the required threshold
of harm in support of a party to the conflict and to the detriment of another
(belligerent nexus).
VI. Beginning and end of direct participation in hostilities

Measures preparatory to the execution of a specific act of direct participation in
hostilities, as well as the deployment to and the return from the location of its
execution, constitute an integral part of that act.
VII. Temporal scope of the loss of protection

Civilians lose protection against direct attack for the duration of each specific act
amounting to direct participation in hostilities, whereas members of organized armed
groups belonging to a non-State party to an armed conflict cease to be civilians (see
above II), and lose protection against direct attack, for as long as they assume their
continuous combat function.
VIII. Precautions and presumptions in situations of doubt

All feasible precautions must be taken in determining whether a person is a civilian
and, if so, whether that civilian is directly participating in hostilities. In case of doubt,
the person must be presumed to be protected against direct attack.
IX. Restraints on the use of force in direct attack

In addition to the restraints imposed by international humanitarian law on specific
means and methods of warfare, and without prejudice to further restrictions that may
arise under other applicable branches of international law, the kind and degree of
force which is permissible against persons not entitled to protection against direct
attack must not exceed what is actually necessary to accomplish a legitimate military
purpose in the prevailing circumstances.
X. Consequences of regaining civilian protection

International humanitarian law neither prohibits nor privileges civilian direct
participation in hostilities. When civilians cease to directly participate in hostilities,
or when members of organized armed groups belonging to a non-State party to an
armed conflict cease to assume their continuous combat function, they regain full
civilian protection against direct attack, but are not exempted from prosecution for
violations of domestic and international law they may have committed.
8 Document No. 51
Part 2: RECOMMENDATIONS AND COMMENTARY
A. THE CONCEPT OF CIVILIAN

For the purposes of the principle of distinction, the definition of civilian refers to those
persons who enjoy immunity from direct attack unless and for such time as they
take a direct part in hostilities. Where IHL provides persons other than civilians with
immunity from direct attack, the loss and restoration of protection is governed by
criteria similar to, but not necessarily identical with, direct participation in hostilities.
Before interpreting the notion of direct participation in hostilities itself, it will therefore
be necessary to clarify the concept of civilian under IHL applicable in international and
non-international armed conflict.
I. The concept of civilian in international armed conflict

For the purposes of the principle of distinction in international armed conflict,
all persons who are neither members of the armed forces of a party to the
conflict nor participants in a levée en masse are civilians and, therefore, entitled
to protection against direct attack unless and for such time as they take a direct
part in hostilities.
1. Mutual exclusiveness of the concepts of civilian, armed forces and levée en

masse
According to Additional Protocol I (AP I), in situations of international armed conflict,
civilians are defined negatively as all persons who are neither members of the armed
forces of a party to the conflict nor participants in a levée en masse.
While treaty IHL predating Additional Protocol I does not expressly define civilians, the
terminology used in the Hague Regulations (H IV R) and the four Geneva Conventions
(GC I-IV) nevertheless suggests that the concepts of civilian, of armed forces, and of
levée en masse are mutually exclusive, and that every person involved in, or affected
by, the conduct of hostilities falls into one of these three categories. In other words,
under all instruments governing international armed conflict, the concept of civilian is
negatively delimited by the definitions of armed forces and of levée en masse, both of
which shall in the following be more closely examined.
2. Armed forces
a) Basic concept
According to Additional Protocol I, the armed forces of a party to the conflict comprise
all organized armed forces, groups and units which are under a command responsible
to that party for the conduct of its subordinates. At first glance, this broad and
functional concept of armed forces seems wider than that underlying the Hague
Regulations and the Geneva Conventions. Although these treaties do not expressly
define armed forces, they require that members of militias and volunteer corps
other than the regular armed forces recognized as such in domestic law fulfil four
requirements: (a) responsible command; (b) fixed distinctive sign recognizable at a
distance; (c) carrying arms openly; and (d) operating in accordance with the laws and
customs of war. Strictly speaking, however, these requirements constitute conditions
for the post-capture entitlement of irregular armed forces to combatant privilege and
prisoner-of-war status and are not constitutive elements of the armed forces of a party
to a conflict.
Thus, while members of irregular armed forces failing to fulfil the four requirements
may not be entitled to combatant privilege and prisoner-of-war status after capture,
[Footnote: In the ICRC’s view, in international armed conflict, any person failing to qualify for prisoner-of-war
status under Art. 4 GC III must be afforded the fundamental guarantees set out in Art. 75 AP I, which have
attained customary nature and, subject to the nationality requirements of Art. 4 GC IV, also remains a “protected
person” within the meaning of GC IV.]
it does not follow that any such person must necessarily be excluded from the category
of armed forces and regarded as a civilian for the purposes of the conduct of hostilities.
On the contrary, it would contradict the logic of the principle of distinction to place
irregular armed forces under the more protective legal regime afforded to the civilian
population merely because they fail to distinguish themselves from that population,
to carry their arms openly, or to conduct their operations in accordance with the laws
and customs of war. Therefore, even under the terms of the Hague Regulations and
the Geneva Conventions, all armed actors showing a sufficient degree of military
organization and belonging to a party to the conflict must be regarded as part of the
armed forces of that party.
[Footnote: While the prevailing opinion during the 2006 expert meeting was supportive of this interpretation,
some concerns were expressed that this approach could be misunderstood as creating a category of persons
protected neither by GC III nor by GC IV (Report DPH 2006, pp. 15 f.). For the ICRC’s position in this respect see,
e.g., above N 15.]
b) Meaning and significance of “belonging to” a party to the conflict

In order for organized armed groups to qualify as armed forces under IHL, they must
belong to a party to the conflict. While this requirement is made textually explicit only
for irregular militias and volunteer corps, including organized resistance movements,
it is implied wherever the treaties refer to the armed forces “of” a party to the conflict.
The concept of “belonging to” requires at least a de facto relationship between an
organized armed group and a party to the conflict. This relationship may be officially
declared, but may also be expressed through tacit agreement or conclusive behaviour
that makes clear for which party the group is fighting. Without any doubt, an organized
armed group can be said to belong to a State if its conduct is attributable to that State
under the international law of State responsibility. The degree of control required to
make a State responsible for the conduct of an organized armed group is not settled
in international law. In practice, in order for an organized armed group to belong to a
party to the conflict, it appears essential that it conduct hostilities on behalf and with
the agreement of that party.
Groups engaging in organized armed violence against a party to an international armed
conflict without belonging to another party to the same conflict cannot be regarded
as members of the armed forces of a party to that conflict, whether under Additional
Protocol I, the Hague Regulations, or the Geneva Conventions. They are thus civilians
10 Document No. 51
under those three instruments. Any other view would discard the dichotomy in all
armed conflicts between the armed forces of the parties to the conflict and the civilian
population; it would also contradict the definition of international armed conflicts
as confrontations between States and not between States and non-State actors.
Organized armed groups operating within the broader context of an international
armed conflict without belonging to a party to that conflict could still be regarded
as parties to a separate non-international armed conflict provided that the violence
reaches the required threshold. Whether the individuals are civilians or members of
the armed forces of a party to the conflict would then have to be determined under
IHL governing non-international armed conflicts.
Lastly, it should be pointed out that organized armed violence failing to qualify as an
international or non-international armed conflict remains an issue of law enforcement,
whether the perpetrators are viewed as rioters, terrorists, pirates, gangsters, hostage-
takers or other organized criminals.
c) Determination of membership
For the regular armed forces of States, individual membership is generally regulated
by domestic law and expressed through formal integration into permanent units
distinguishable by uniforms, insignia, and equipment. The same applies where armed
units of police, border guard, or similar uniformed forces are incorporated into State
armed forces. Members of regularly constituted forces are not civilians, regardless of
their individual conduct or the function they assume within the armed forces. For the
purposes of the principle of distinction, membership in regular State armed forces
ceases, and civilian protection is restored, when a member disengages from active
duty and re-integrates into civilian life, whether due to a full discharge from duty or as
a deactivated reservist.
Membership in irregular armed forces, such as militias, volunteer corps, or resistance
movements belonging to a party to the conflict, generally is not regulated by domestic
law and can only be reliably determined on the basis of functional criteria, such as
those applying to organized armed groups in non-international armed conflict.
3. Levée en masse
As far as the levée en masse is concerned, all relevant instruments are based on the
same definition, which refers to the inhabitants of a non-occupied territory who, on
the approach of the enemy, spontaneously take up arms to resist the invading forces
without having had time to form themselves into regular armed units, provided they
carry arms openly and respect the laws and customs of war. Participants in a levée
en masse are the only armed actors who are excluded from the civilian population
although, by definition, they operate spontaneously and lack sufficient organization
and command to qualify as members of the armed forces. All other persons who
directly participate in hostilities on a merely spontaneous, sporadic or unorganized
basis must be regarded as civilians.
4. Conclusion
For the purposes of the principle of distinction in international armed conflict, all
persons who are neither members of the armed forces of a party to the conflict nor
participants in a levée en masse are civilians and, therefore, entitled to protection
against direct attack unless and for such time as they take a direct part in hostilities.
Membership in irregularly constituted militia and volunteer corps, including organized
resistance movements, belonging to a party to the conflict must be determined
based on the same functional criteria that apply to organized armed groups in non-
international armed conflict.
II. The concept of civilian in non-international armed conflict

For the purposes of the principle of distinction in non-international armed
conflict, all persons who are not members of State armed forces or organized
armed groups of a party to the conflict are civilians and, therefore, entitled to
protection against direct attack unless and for such time as they take a direct
part in hostilities. In non-international armed conflict, organized armed groups
constitute the armed forces of a non-State party to the conflict and consist only
of individuals whose continuous function it is to take a direct part in hostilities
(“continuous combat function”).
1. Mutual exclusiveness of the concepts of civilian, armed forces and organized

armed groups
a) Lack of express definitions in treaty law
Treaty IHL governing non-international armed conflict uses the terms civilian, armed
forces and organized armed group without expressly defining them. These concepts
must therefore be interpreted in good faith in accordance with the ordinary meaning
to be given to them in their context and in the light of the object and purpose of IHL.
While it is generally recognized that members of State armed forces in non-
international armed conflict do not qualify as civilians, treaty law, State practice, and
international jurisprudence have not unequivocally settled whether the same applies
to members of organized armed groups (i.e. the armed forces of non-State parties
to an armed conflict). Because organized armed groups generally cannot qualify
as regular armed forces under national law, it might be tempting to conclude that
membership in such groups is simply a continuous form of civilian direct participation
in hostilities. Accordingly, members of organized armed groups would be regarded
as civilians who, owing to their continuous direct participation in hostilities, lose
protection against direct attack for the entire duration of their membership. However,
this approach would seriously undermine the conceptual integrity of the categories of
persons underlying the principle of distinction, most notably because it would create
parties to non-international armed conflicts whose entire armed forces remain part
of the civilian population. As the wording and logic of Article 3 GC I-IV and Additional
Protocol II (AP II) reveals, civilians, armed forces, and organized armed groups of the
12 Document No. 51
parties to the conflict are mutually exclusive categories also in non-international

armed conflict.
b) Article 3 common to the Geneva Conventions

Although Article 3 GC I-IV generally is not considered to govern the conduct of
hostilities, its wording allows certain conclusions to be drawn with regard to the generic
distinction between the armed forces and the civilian population in non-international
armed conflict. Most notably, Article 3 GC I-IV provides that “each Party to the conflict”
must afford protection to “persons taking no active part in the hostilities, including
members of armed forces who have laid down their arms and those placed hors de
combat”. Thus, both State and non-State parties to the conflict have armed forces
distinct from the civilian population. This passage also makes clear that members of
such armed forces, in contrast to other persons, are considered as “taking no active
part in the hostilities” only once they have disengaged from their fighting function
(“have laid down their arms”) or are placed hors de combat; mere suspension of
combat is insufficient. Article 3 GC I-IV thus implies a concept of civilian comprising
those individuals “who do not bear arms” on behalf of a party to the conflict.
c) Additional Protocol II
While Additional Protocol II has a significantly narrower scope of application and uses
terms different from those in Article 3 GC I-IV, the generic categorization of persons
is the same in both instruments. During the Diplomatic Conference of 1974-77, Draft
Article 25 [1] AP II defined the concept of civilian as including “anyone who is not a
member of the armed forces or of an organized armed group”. Although this article
was discarded along with most other provisions on the conduct of hostilities in a last
minute effort to “simplify” the Protocol, the final text continues to reflect the originally
proposed concept of civilian. According to the Protocol, “armed forces”, “dissident
armed forces”, and “other organized armed groups” have the function and ability
“to carry out sustained and concerted military operations”; whereas the “civilian
population and individual civilians shall enjoy general protection against the dangers
arising from military operations” carried out by these forces “unless and for such time
as they take a direct part in hostilities”.
d) Reconciliation of terminology
In Additional Protocol II, the term “armed forces” is restricted to State armed forces,
whereas the armed forces of non-State parties are referred to as “dissident armed
forces” or “other organized armed groups”. The notion of “armed forces” in Article 3
GC I-IV, on the other hand, includes all three categories juxtaposed in Article 1 [1] AP II,
namely State armed forces, dissident armed forces, and other organized armed groups.
Thus, similar to situations of international armed conflict, the concept of civilian in
non-international armed conflict is negatively delimited by the definition of “armed
forces” (Article 3 GC I-IV) or, expressed in the terminology of Additional Protocol II, of
State “armed forces”, “dissident armed forces” and “other organized armed groups”.
For the purposes of this Interpretive Guidance, the armed forces of States party to
a non-international armed conflict are referred to as “State armed forces”, whereas

the armed forces of non-State parties are described as “organized armed groups”.
Where not stated otherwise, the concept of “organized armed group” includes both
“dissident armed forces” and “other organized armed groups” (Article 1 [1] AP II).
2. State armed forces

a) Basic concept
There is no reason to assume that States party to both Additional Protocols desired
distinct definitions of State armed forces in situations of international and non-
international armed conflict. According to the travaux préparatoires for Additional
Protocol II, the concept of armed forces of a High Contracting Party in Article 1 [1] AP
II was intended to be broad enough to include armed actors who do not necessarily
qualify as armed forces under domestic law, such as members of the national guard,
customs, or police forces, provided that they do, in fact, assume the function of armed
forces. Thus, comparable to the concept of armed forces in Additional Protocol I, State
armed forces under Additional Protocol II include both the regular armed forces and
other armed groups or units organized under a command responsible to the State.
b) Determination of membership
At least as far as regular armed forces are concerned, membership in State armed forces
is generally defined by domestic law and expressed through formal integration into
permanent units distinguishable by uniforms, insignia and equipment. The same applies
where armed units of police, border guard, or similar uniformed forces are incorporated
into the armed forces. Members of regularly constituted forces are not civilians,
regardless of their individual conduct or of the function they assume within the armed
forces. For the purposes of the principle of distinction, membership in regular State
armed forces ceases, and civilian protection is restored, when a member disengages
from active duty and re-integrates into civilian life, whether due to a full discharge from
duty or as a deactivated reservist. Just as in international armed conflict, membership in
irregular State armed forces, such as militia, volunteer or paramilitary groups, generally
is not regulated by domestic law and can only be reliably determined on the basis of the
same functional criteria that apply to organized armed groups of non-State parties to the
conflict.
3. Organized armed groups

a) Basic concept
Organized armed groups belonging to a non-State party to an armed conflict include
both dissident armed forces and other organized armed groups. Dissident armed
forces essentially constitute part of a State’s armed forces that have turned against the
government. Other organized armed groups recruit their members primarily from the
civilian population but develop a sufficient degree of military organization to conduct
hostilities on behalf of a party to the conflict, albeit not always with the same means,
intensity and level of sophistication as State armed forces.
14 Document No. 51
In both cases, it is crucial for the protection of the civilian population to distinguish a
non-State party to a conflict (e.g., an insurgency, a rebellion, or a secessionist movement)
from its armed forces (i.e., an organized armed group). As with State parties to armed
conflicts, non-State parties comprise both fighting forces and supportive segments of
the civilian population, such as political and humanitarian wings. The term organized
armed group, however, refers exclusively to the armed or military wing of a non-State
party: its armed forces in a functional sense. This distinction has important consequences
for the determination of membership in an organized armed group as opposed to other
forms of affiliation with, or support for, a non-State party to the conflict.
b) Determination of membership
Dissident armed forces: Although members of dissident armed forces are no longer
members of State armed forces, they do not become civilians merely because they
have turned against their government. At least to the extent, and for as long as, they
remain organized under the structures of the State armed forces to which they formerly
belonged, these structures should continue to determine individual membership in
dissident armed forces as well.
Other organized armed groups: More difficult is the concept of membership in
organized armed groups other than dissident armed forces. Membership in these
irregularly constituted groups has no basis in domestic law. It is rarely formalized
through an act of integration other than taking up a certain function for the group;
and it is not consistently expressed through uniforms, fixed distinctive signs, or
identification cards. In view of the wide variety of cultural, political, and military
contexts in which organized armed groups operate, there may be various degrees of
affiliation with such groups that do not necessarily amount to “membership” within
the meaning of IHL. In one case, affiliation may turn on individual choice, in another
on involuntary recruitment, and in yet another on more traditional notions of clan
or family. In practice, the informal and clandestine structures of most organized
armed groups and the elastic nature of membership render it particularly difficult to
distinguish between a non-State party to the conflict and its armed forces.
As has been shown above, in IHL governing non-international armed conflict, the concept
of organized armed group refers to non-State armed forces in a strictly functional sense.
For the practical purposes of the principle of distinction, therefore, membership in such
groups cannot depend on abstract affiliation, family ties, or other criteria prone to error,
arbitrariness or abuse. Instead, membership must depend on whether the continuous
function assumed by an individual corresponds to that collectively exercised by the
group as a whole, namely the conduct of hostilities on behalf of a non-State party to
the conflict. Consequently, under IHL, the decisive criterion for individual membership
in an organized armed group is whether a person assumes a continuous function for
the group involving his or her direct participation in hostilities (hereafter: “continuous
combat function”). Continuous combat function does not imply de jure entitlement to
combatant privilege. Rather, it distinguishes members of the organized fighting forces
of a non-State party from civilians who directly participate in hostilities on a merely
spontaneous, sporadic, or unorganized basis, or who assume exclusively political,

administrative or other non-combat functions.
Continuous combat function requires lasting integration into an organized armed
group acting as the armed forces of a non-State party to an armed conflict. Thus,
individuals whose continuous function involves the preparation, execution, or
command of acts or operations amounting to direct participation in hostilities are
assuming a continuous combat function. An individual recruited, trained and equipped
by such a group to continuously and directly participate in hostilities on its behalf can
be considered to assume a continuous combat function even before he or she first
carries out a hostile act. This case must be distinguished from persons comparable to
reservists who, after a period of basic training or active membership, leave the armed
group and reintegrate into civilian life. Such “reservists” are civilians until and for such
time as they are called back to active duty.
Individuals who continuously accompany or support an organized armed group, but
whose function does not involve direct participation in hostilities, are not members of
that group within the meaning of IHL. Instead, they remain civilians assuming support
functions, similar to private contractors and civilian employees accompanying State
armed forces. Thus, recruiters, trainers, financiers and propagandists may continuously
contribute to the general war effort of a non-State party, but they are not members of
an organized armed group belonging to that party unless their function additionally
includes activities amounting to direct participation in hostilities. The same applies
to individuals whose function is limited to the purchasing, smuggling, manufacturing
and maintaining of weapons and other equipment outside specific military operations
or to the collection of intelligence other than of a tactical nature. Although such
persons may accompany organized armed groups and provide substantial support
to a party to the conflict, they do not assume continuous combat function and, for
the purposes of the principle of distinction, cannot be regarded as members of an
organized armed group. As civilians, they benefit from protection against direct attack
unless and for such time as they directly participate in hostilities, even though their
activities or location may increase their exposure to incidental death or injury.
In practice, the principle of distinction must be applied based on information which
is practically available and can reasonably be regarded as reliable in the prevailing
circumstances. A continuous combat function may be openly expressed through
the carrying of uniforms, distinctive signs, or certain weapons. Yet it may also be
identified on the basis of conclusive behaviour, for example where a person has
repeatedly directly participated in hostilities in support of an organized armed group
in circumstances indicating that such conduct constitutes a continuous function
rather than a spontaneous, sporadic, or temporary role assumed for the duration of
a particular operation. Whatever criteria are applied in implementing the principle of
distinction in a particular context, they must allow to reliably distinguish members
of the armed forces of a non-State party to the conflict from civilians who do not
directly participate in hostilities, or who do so on a merely spontaneous, sporadic or
unorganized basis. As will be shown, that determination remains subject to all feasible
precautions and to the presumption of protection in case of doubt.
16 Document No. 51
4. Conclusion
For the purposes of the principle of distinction in non-international armed conflict,
all persons who are not members of State armed forces or organized armed groups
of a party to the conflict are civilians and, therefore, entitled to protection against
direct attack unless and for such time as they take a direct part in hostilities. In non-
international armed conflict, organized armed groups constitute the armed forces
of a non-State party to the conflict and consist only of individuals whose continuous
function it is to take a direct part in hostilities (“continuous combat function”).
III. Private contractors and civilian employees

Private contractors and employees of a party to an armed conflict who are
civilians (see above I and II) are entitled to protection against direct attack
unless and for such time as they take a direct part in hostilities. Their activities
or location may, however, expose them to an increased risk of incidental death
or injury even if they do not take a direct part in hostilities.
1. Particular difficulties related to private contractors and civilian employees

In recent decades, parties to armed conflicts have increasingly employed private
contractors and civilian employees in a variety of functions traditionally performed by
military personnel. Generally speaking, whether private contractors and employees of
a party to an armed conflict are civilians within the meaning of IHL and whether they
directly participate in hostilities depends on the same criteria as would apply to any
other civilian. The special role of such personnel requires that these determinations
be made with particular care and with due consideration for the geographic and
organizational closeness of many private contractors and civilian employees to the
armed forces and the hostilities.
It should also be noted that the purpose of the distinction between civilians and members
of the armed forces may not be identical under domestic and international law. Depending
on national legislation, membership in the armed forces may have administrative,
jurisdictional, and other consequences irrelevant to the principle of distinction in the
conduct of hostilities. Under IHL, the primary consequences of membership in the armed
forces are the exclusion from the category of civilian and, in international armed conflict,
the right to directly participate in hostilities on behalf of a party to the conflict (combatant
privilege). Where the concepts of civilian and armed forces are defined for the purpose of
the conduct of hostilities, the relevant standards must be derived from IHL.
The great majority of private contractors and civilian employees currently active in
armed conflicts have not been incorporated into State armed forces and assume
functions that clearly do not involve their direct participation in hostilities on behalf of
a party to the conflict (i.e. no continuous combat function). Therefore, under IHL, they
generally come within the definition of civilians. Although they are thus entitled to
protection against direct attack, their proximity to the armed forces and other military
objectives may expose them more than other civilians to the dangers arising from
military operations, including the risk of incidental death or injury.
In some cases, however, it may be extremely difficult to determine the civilian or military
nature of contractor activity. For example, the line between the defence of military
personnel and other military objectives against enemy attacks (direct participation
in hostilities) and the protection of those same persons and objects against crime or
violence unrelated to the hostilities (law enforcement / defence of self or others) may
be thin. It is therefore particularly important in this context to observe the general
rules of IHL on precautions and presumptions in situations of doubt.
2. International armed conflict

Civilians, including those formally authorized to accompany the armed forces and
entitled to prisoner-of-war status upon capture, were never meant to directly participate
in hostilities on behalf of a party to the conflict. As long as they are not incorporated
into the armed forces, private contractors and civilian employees do not cease to be
civilians simply because they accompany the armed forces and or assume functions
other than the conduct of hostilities that would traditionally have been performed by
military personnel. Where such personnel directly participate in hostilities without the
express or tacit authorization of the State party to the conflict, they remain civilians and
lose their protection against direct attack for such time as their direct participation lasts.
A different conclusion must be reached for contractors and employees who, to all
intents and purposes, have been incorporated into the armed forces of a party to
the conflict, whether through a formal procedure under national law or de facto by
being given a continuous combat function. Under IHL, such personnel would become
members of an organized armed force, group, or unit under a command responsible
to a party to the conflict and, for the purposes of the principle of distinction, would no
longer qualify as civilians.
3. Non-international armed conflict

The above observations also apply, mutatis mutandis, in non-international armed
conflicts. Thus, for such time as private contractors assume a continuous combat function
for an organized armed group belonging to a non-State party, they become members of
that group. Theoretically, private military companies could even become independent
non-State parties to a non-international armed conflict. Private contractors and civilian
employees who are neither members of State armed forces nor members of organized
armed groups, however, must be regarded as civilians and, therefore, are protected
against direct attack unless and for such time as they directly participate in hostilities.
4. Conclusion
Whether private contractors and employees of a party to the conflict qualify as
civilians within the meaning of IHL and whether they directly participate in hostilities
depends on the same criteria as are applicable to any other civilian. The geographic
and organizational closeness of such personnel to the armed forces and the hostilities
require that this determination be made with particular care. Those who qualify as
civilians are entitled to protection against direct attack unless and for such time as
18 Document No. 51
they directly participate in hostilities, even though their activities and location may
expose them to an increased risk of incidental injury and death. This does not rule out
the possibility that, for purposes other than the conduct of hostilities, domestic law
might regulate the status of private contractors and employees differently from IHL.
B. THE CONCEPT OF DIRECT PARTICIPATION IN HOSTILITIES

Treaty IHL does not define direct participation in hostilities, nor does a clear
interpretation of the concept emerge from State practice or international jurisprudence.
The notion of direct participation in hostilities must therefore be interpreted in good
faith in accordance with the ordinary meaning to be given to its constituent terms in
their context and in light of the object and purpose of IHL.
Where treaty law refers to hostilities, that notion is intrinsically linked to situations
of international or non-international armed conflict. Therefore, the concept of direct
participation in hostilities cannot refer to conduct occurring outside situations of
armed conflict, such as during internal disturbances and tensions, including riots,
isolated and sporadic acts of violence and other acts of a similar nature. Moreover,
even during armed conflict, not all conduct constitutes part of the hostilities. It is the
purpose of the present chapter to identify the criteria that determine whether and,
if so, for how long a particular conduct amounts to direct participation in hostilities.
In practice, civilian participation in hostilities occurs in various forms and degrees
of intensity and in a wide variety of geographical, cultural, political, and military
contexts. Therefore, in determining whether a particular conduct amounts to direct
participation in hostilities, due consideration must be given to the circumstances
prevailing at the relevant time and place. Nevertheless, the importance of the
circumstances surrounding each case should not divert attention from the fact that
direct participation in hostilities remains a legal concept of limited elasticity that
must be interpreted in a theoretically sound and coherent manner reflecting the
fundamental principles of IHL.
IV. Direct participation in hostilities as a specific act

The notion of direct participation in hostilities refers to specific acts carried out
by individuals as part of the conduct of hostilities between parties to an armed
conflict.
1. Basic components of the notion of direct participation in hostilities

The notion of direct participation in hostilities essentially comprises two elements,
namely that of “hostilities” and that of “direct participation” therein. While the concept
of “hostilities” refers to the (collective) resort by the parties to the conflict to means and
methods of injuring the enemy, “participation” in hostilities refers to the (individual)
involvement of a person in these hostilities. Depending on the quality and degree of
such involvement, individual participation in hostilities may be described as “direct” or
“indirect”. The notion of direct participation in hostilities has evolved from the phrase
“taking no active part in the hostilities” used in Article 3 GC I-IV. Although the English
texts of the Geneva Conventions and Additional Protocols use the words “active” and
“direct”, respectively, the consistent use of the phrase “participent directement” in the
equally authentic French texts demonstrate that the terms “direct” and “active” refer to
the same quality and degree of individual participation in hostilities. Furthermore, as
the notion of taking a direct part in hostilities is used synonymously in the Additional
Protocols I and II, it should be interpreted in the same manner in international and
non-international armed conflict.
2. Restriction to specific acts

In treaty IHL, individual conduct that constitutes part of the hostilities is described as
direct participation in hostilities, regardless of whether the individual is a civilian or a
member of the armed forces. Whether individuals directly participate in hostilities on a
spontaneous, sporadic, or unorganized basis or as part of a continuous function assumed
for an organized armed force or group belonging to a party to the conflict may be
decisive for their status as civilians, but has no influence on the scope of conduct that
constitutes direct participation in hostilities. This illustrates that the notion of direct
participation in hostilities does not refer to a person’s status, function, or affiliation, but
to his or her engagement in specific hostile acts. In essence, the concept of hostilities
could be described as the sum total of all hostile acts carried out by individuals directly
participating in hostilities.
Where civilians engage in hostile acts on a persistently recurrent basis, it may be
tempting to regard not only each hostile act as direct participation in hostilities, but even
their continued intent to carry out unspecified hostile acts in the future. However, any
extension of the concept of direct participation in hostilities beyond specific acts would
blur the distinction made in IHL between temporary, activity-based loss of protection
(due to direct participation in hostilities), and continuous, status- or function-based loss
of protection (due to combatant status or continuous combat function). In practice,
confusing the distinct regimes by which IHL governs the loss of protection for civilians
and for members of State armed forces or organized armed groups would provoke
insurmountable evidentiary problems. Those conducting hostilities already face the
difficult task of distinguishing between civilians who are and civilians who are not
engaged in a specific hostile act (direct participation in hostilities), and distinguishing
both of these from members of organized armed groups (continuous combat function)
and State armed forces. In operational reality, it would be impossible to determine with
a sufficient degree of reliability whether civilians not currently preparing or executing a
hostile act have previously done so on a persistently recurrent basis and whether they
have the continued intent to do so again. Basing continuous loss of protection on such
speculative criteria would inevitably result in erroneous or arbitrary attacks against
civilians, thus undermining their protection which is at the heart of IHL. Consequently,
in accordance with the object and purpose of IHL, the concept of direct participation in
hostilities must be interpreted as restricted to specific hostile acts.
20 Document No. 51
3. Conclusion
The notion of direct participation in hostilities refers to specific hostile acts carried
out by individuals as part of the conduct of hostilities between parties to an armed
conflict. It must be interpreted synonymously in situations of international and non-
international armed conflict. The treaty terms of “direct” and “active” indicate the
same quality and degree of individual participation in hostilities.
V. Constitutive elements of direct participation in hostilities

In order to qualify as direct participation in hostilities, a specific act must meet
the following cumulative criteria:
1. The act must be likely to adversely affect the military operations or military
capacity of a party to an armed conflict or, alternatively, to inflict death,
injury, or destruction on persons or objects protected against direct attack
(threshold of harm), and
2. There must be a direct causal link between the act and the harm likely to
result either from that act, or from a coordinated military operation of which
that act constitutes an integral part (direct causation), and
3. The act must be specifically designed to directly cause the required threshold
of harm in support of a party to the conflict and to the detriment of another
(belligerent nexus).
Acts amounting to direct participation in hostilities must meet three cumulative
requirements: (1) a threshold regarding the harm likely to result from the act, (2) a
relationship of direct causation between the act and the expected harm, and (3) a
belligerent nexus between the act and the hostilities conducted between the parties
to an armed conflict. Although these elements are very closely interrelated, and
although there may be areas of overlap between them, each of them will be discussed
separately here.
1. Threshold of harm
In order to reach the required threshold of harm, a specific act must be likely
to adversely affect the military operations or military capacity of a party to an
armed conflict or, alternatively, to inflict death, injury, or destruction on persons
or objects protected against direct attack.
For a specific act to qualify as direct participation in hostilities, the harm likely to result
from it must attain a certain threshold. This threshold can be reached either by causing
harm of a specifically military nature or by inflicting death, injury, or destruction on
persons or objects protected against direct attack. The qualification of an act as direct
participation does not require the materialization of harm reaching the threshold
but merely the objective likelihood that the act will result in such harm. Therefore,
the relevant threshold determination must be based on “likely” harm, that is to say,
harm which may reasonably be expected to result from an act in the prevailing
circumstances.
a) Adversely affecting the military operations or military capacity of a party to

the conflict
When an act may reasonably be expected to cause harm of a specifically military
nature, the threshold requirement will generally be satisfied regardless of quantitative
gravity. In this context, military harm should be interpreted as encompassing not only
the infliction of death, injury, or destruction on military personnel and objects, but
essentially any consequence adversely affecting the military operations or military
capacity of a party to the conflict.
For example, beyond the killing and wounding of military personnel and the
causation of physical or functional damage to military objects, the military operations
or military capacity of a party to the conflict can be adversely affected by sabotage
and other armed or unarmed activities restricting or disturbing deployments, logistics
and communication. Adverse effects may also arise from capturing or otherwise
establishing or exercising control over military personnel, objects and territory to
the detriment of the adversary. For instance, denying the adversary the military use
of certain objects, equipment and territory, guarding captured military personnel
of the adversary to prevent them being forcibly liberated (as opposed to exercising
authority over them), and clearing mines placed by the adversary would reach the
required threshold of harm. Electronic interference with military computer networks
could also suffice, whether through computer network attacks (CNA) or computer
network exploitation (CNE), as well as wiretapping the adversary’s high command103
or transmitting tactical targeting information for an attack.
At the same time, the conduct of a civilian cannot be interpreted as adversely affecting
the military operations or military capacity of a party to the conflict simply because it
fails to positively affect them. Thus, the refusal of a civilian to collaborate with a party to
the conflict as an informant, scout or lookout would not reach the required threshold
of harm regardless of the motivations underlying the refusal.
b) Inflicting death, injury or destruction on persons or objects protected against

direct attack
Specific acts may constitute part of the hostilities even if they are not likely to
adversely affect the military operations or military capacity of a party to the conflict.
In the absence of such military harm, however, a specific act must be likely to cause
at least death, injury, or destruction. The most uncontroversial examples of acts that
can qualify as direct participation in hostilities even in the absence of military harm
are attacks directed against civilians and civilian objects. In IHL, attacks are defined
as “acts of violence against the adversary, whether in offence or in defence”. The
phrase “against the adversary” does not specify the target, but the belligerent nexus
of an attack, so that even acts of violence directed specifically against civilians or
civilian objects may amount to direct participation in hostilities. For example, sniper
attacks against civilians and the bombardment or shelling of civilian villages or urban
residential areas are likely to inflict death, injury, or destruction on persons and objects
protected against direct attack and thus qualify as direct participation in hostilities
regardless of any military harm to the opposing party to the conflict.
22 Document No. 51
Acts that neither cause harm of a military nature nor inflict death, injury, or destruction
on protected persons or objects cannot be equated with the use of means or
methods of “warfare” or, respectively, of “injuring the enemy”, as would be required
for a qualification as hostilities. For example, the building of fences or road blocks, the
interruption of electricity, water, or food supplies, the appropriation of cars and fuel, the
manipulation of computer networks, and the arrest or deportation of persons may have
a serious impact on public security, health, and commerce, and may even be prohibited
under IHL. However, they would not, in the absence of adverse military effects, cause
the kind and degree of harm required to qualify as direct participation in hostilities.
c) Summary
For a specific act to reach the threshold of harm required to qualify as direct participation
in hostilities, it must be likely to adversely affect the military operations or military
capacity of a party to an armed conflict. In the absence of military harm, the threshold
can also be reached where an act is likely to inflict death, injury, or destruction on
persons or objects protected against direct attack. In both cases, acts reaching the
required threshold of harm can only amount to direct participation in hostilities if they
additionally satisfy the requirements of direct causation and belligerent nexus.
2. Direct causation
In order for the requirement of direct causation to be satisfied, there must be a
direct causal link between a specific act and the harm likely to result either from
that act, or from a coordinated military operation of which that act constitutes an
integral part.
a) Conduct of hostilities, general war effort, and war sustaining activities

The treaty terminology of taking a “direct” part in hostilities, which describes civilian
conduct entailing loss of protection against direct attack, implies that there can also
be “indirect” participation in hostilities, which does not lead to such loss of protection.
Indeed, the distinction between a person’s direct and indirect participation in
hostilities corresponds, at the collective level of the opposing parties to an armed
conflict, to that between the conduct of hostilities and other activities that are part of
the general war effort or may be characterized as war-sustaining activities.
Generally speaking, beyond the actual conduct of hostilities, the general war effort
could be said to include all activities objectively contributing to the military defeat
of the adversary (e.g. design, production and shipment of weapons and military
equipment, construction or repair of roads, ports, airports, bridges, railways and
other infrastructure outside the context of concrete military operations), while war
sustaining activities would additionally include political, economic or media activities
supporting the general war effort (e.g. political propaganda, financial transactions,
production of agricultural or non-military industrial goods).
Admittedly, both the general war effort and war-sustaining activities may ultimately
result in harm reaching the threshold required for a qualification as direct participation
in hostilities. Some of these activities may even be indispensable to harming the

adversary, such as providing finances, food and shelter to the armed forces and
producing weapons and ammunition. However, unlike the conduct of hostilities,
which is designed to cause – i.e. bring about the materialization of – the required
harm, the general war effort and war sustaining activities also include activities that
merely maintain or build up the capacity to cause such harm.
b) Direct and indirect causation

For a specific act to qualify as “direct” rather than “indirect” participation in hostilities
there must be a sufficiently close causal relation between the act and the resulting
harm. Standards such as “indirect causation of harm” or “materially facilitating harm”
are clearly too wide, as they would bring the entire war effort within the concept of
direct participation in hostilities and, thus, would deprive large parts of the civilian
population of their protection against direct attack. Instead, the distinction between
direct and indirect participation in hostilities must be interpreted as corresponding to
that between direct and indirect causation of harm.
In the present context, direct causation should be understood as meaning that the
harm in question must be brought about in one causal step. Therefore, individual
conduct that merely builds up or maintains the capacity of a party to harm its adversary,
or which otherwise only indirectly causes harm, is excluded from the concept of direct
participation in hostilities. For example, imposing a regime of economic sanctions on
a party to an armed conflict, depriving it of financial assets, or providing its adversary
with supplies and services (such as electricity, fuel, construction material, finances and
financial services) would have a potentially important, but still indirect, impact on the
military capacity or operations of that party. Other examples of indirect participation
include scientific research and design, as well as production and transport of weapons
and equipment unless carried out as an integral part of a specific military operation
designed to directly cause the required threshold of harm. Likewise, although the
recruitment and training of personnel is crucial to the military capacity of a party to the
conflict, the causal link with the harm inflicted on the adversary will generally remain
indirect. Only where persons are specifically recruited and trained for the execution of
a predetermined hostile act can such activities be regarded as an integral part of that
act and, therefore, as direct participation in hostilities.
Moreover, for the requirement of direct causation to be met, it is neither necessary
nor sufficient that the act be indispensable to the causation of harm. For example, the
financing or production of weapons and the provision of food to the armed forces
may be indispensable, but not directly causal, to the subsequent infliction of harm.
On the other hand, a person serving as one of several lookouts during an ambush
would certainly be taking a direct part in hostilities although his contribution may
not be indispensable to the causation of harm. Finally, it is not sufficient that the act
and its consequences be connected through an uninterrupted causal chain of events.
For example, the assembly and storing of an improvised explosive device (IED) in a
workshop, or the purchase or smuggling of its components, may be connected with
24 Document No. 51
the resulting harm through an uninterrupted causal chain of events, but, unlike the
planting and detonation of that device, do not cause that harm directly.
c) Direct causation in collective operations

The required standard of direct causation of harm must take into account the collective
nature and complexity of contemporary military operations. For example, attacks
carried out by unmanned aerial vehicles may simultaneously involve a number of
persons, such as computer specialists operating the vehicle through remote control,
individuals illuminating the target, aircraft crews collecting data, specialists controlling
the firing of missiles, radio operators transmitting orders, and an overall commander.
While all of these persons are integral to that operation and directly participate in
hostilities, only few of them carry out activities that, in isolation, could be said to
directly cause the required threshold of harm. The standard of direct causation must
therefore be interpreted to include conduct that causes harm only in conjunction with
other acts. More precisely, where a specific act does not on its own directly cause the
required threshold of harm, the requirement of direct causation would still be fulfilled
where the act constitutes an integral part of a concrete and coordinated tactical
operation that directly causes such harm. Examples of such acts would include, inter
alia, the identification and marking of targets, the analysis and transmission of tactical
intelligence to attacking forces, and the instruction and assistance given to troops for
the execution of a specific military operation.
d) Causal, temporal, and geographic proximity

The requirement of direct causation refers to a degree of causal proximity, which
should not be confused with the merely indicative elements of temporal or geographic
proximity. For example, it has become quite common for parties to armed conflicts to
conduct hostilities through delayed (i.e. temporally remote) weapons-systems, such as
mines, booby-traps and timer-controlled devices, as well as through remote-controlled
(i.e. geographically remote) missiles, unmanned aircraft and computer network attacks.
The causal relationship between the employment of such means and the ensuing harm
remains direct regardless of temporal or geographical proximity. Conversely, although
the delivery or preparation of food for combatant forces may occur in the same place
and at the same time as the fighting, the causal link between such support activities
and the causation of the required threshold of harm to the opposing party to a conflict
remains indirect. Thus, while temporal or geographic proximity to the resulting harm
may indicate that a specific act amounts to direct participation in hostilities, these
factors would not be sufficient in the absence of direct causation. As previously noted,
where the required harm has not yet materialized, the element of direct causation must
be determined by reference to the harm that can reasonably be expected to directly
result from a concrete act or operation (“likely” harm).
e) Selected examples
Driving an ammunition truck: The delivery by a civilian truck driver of ammunition to
an active firing position at the front line would almost certainly have to be regarded as
an integral part of ongoing combat operations and, therefore, as direct participation

in hostilities. Transporting ammunition from a factory to a port for further shipping
to a storehouse in a conflict zone, on the other hand, is too remote from the use of
that ammunition in specific military operations to cause the ensuing harm directly.
Although the ammunition truck remains a legitimate military objective, the driving of
the truck would not amount to direct participation in hostilities and would not deprive
a civilian driver of protection against direct attack. Therefore, any direct attack against
the truck would have to take the probable death of the civilian driver into account in
the proportionality assessment.
Voluntary human shields: The same logic applies to civilians attempting to shield a
military objective by their presence as persons entitled to protection against direct
attack (voluntary human shields). Where civilians voluntarily and deliberately position
themselves to create a physical obstacle to military operations of a party to the conflict,
they could directly cause the threshold of harm required for a qualification as direct
participation in hostilities. This scenario may become particularly relevant in ground
operations, such as in urban environments, where civilians may attempt to give
physical cover to fighting personnel supported by them or to inhibit the movement of
opposing infantry troops.
Conversely, in operations involving more powerful weaponry, such as artillery or air
attacks, the presence of voluntary human shields often has no adverse impact on the
capacity of the attacker to identify and destroy the shielded military objective. Instead,
the presence of civilians around the targeted objective may shift the parameters of
the proportionality assessment to the detriment of the attacker, thus increasing the
probability that the expected incidental harm would have to be regarded as excessive
in relation to the anticipated military advantage. The very fact that voluntary human
shields are in practice considered to pose a legal – rather than a physical – obstacle to
military operations demonstrates that they are recognized as protected against direct
attack or, in other words, that their conduct does not amount to direct participation in
hostilities. Indeed, although the presence of voluntary human shields may eventually
lead to the cancellation or suspension of an operation by the attacker, the causal
relation between their conduct and the resulting harm remains indirect. Depending
on the circumstances, it may also be questionable whether voluntary human shielding
reaches the required threshold of harm.
The fact that some civilians voluntarily and deliberately abuse their legal entitlement
to protection against direct attack in order to shield military objectives does not,
without more, entail the loss of their protection and their liability to direct attack
independently of the shielded objective. Nevertheless, through their voluntary
presence near legitimate military objectives, voluntary human shields are particularly
exposed to the dangers of military operations and, therefore, incur an increased risk of
suffering incidental death or injury during attacks against those objectives.
26 Document No. 51
f) Summary
The requirement of direct causation is satisfied if either the specific act in question, or a
concrete and coordinated military operation of which that act constitutes an integral part,
may reasonably be expected to directly – in one causal step – cause harm that reaches
the required threshold. However, even acts meeting the requirements of direct causation
and reaching the required threshold of harm can only amount to direct participation in
hostilities if they additionally satisfy the third requirement, that of belligerent nexus.
3. Belligerent nexus
In order to meet the requirement of belligerent nexus, an act must be specifically
designed to directly cause the required threshold of harm in support of a party
to the conflict and to the detriment of another.
a) Basic Concept
Not every act that directly adversely affects the military operations or military capacity
of a party to an armed conflict or directly inflicts death, injury, or destruction on persons
and objects protected against direct attack necessarily amounts to direct participation
in hostilities. As noted, the concept of direct participation in hostilities is restricted to
specific acts that are so closely related to the hostilities conducted between parties
to an armed conflict that they constitute an integral part of those hostilities. Treaty
IHL describes the term hostilities as the resort to means and methods of “injuring the
enemy”, and individual attacks as being directed “against the adversary”. In other
words, in order to amount to direct participation in hostilities, an act must not only
be objectively likely to inflict harm that meets the first two criteria, but it must also be
specifically designed to do so in support of a party to an armed conflict and to the detriment
of another (belligerent nexus).
Conversely, armed violence which is not designed to harm a party to an armed conflict,
or which is not designed to do so in support of another party, cannot amount to any
form of “participation” in hostilities taking place between these parties. Unless such
violence reaches the threshold required to give rise to a separate armed conflict, it
remains of a non-belligerent nature and, therefore, must be addressed through law
enforcement measures.
b) Belligerent nexus and subjective intent

Belligerent nexus should be distinguished from concepts such as subjective intent
and hostile intent. These relate to the state of mind of the person concerned, whereas
belligerent nexus relates to the objective purpose of the act. That purpose is expressed
in the design of the act or operation and does not depend on the mindset of every
participating individual. As an objective criterion linked to the act alone, belligerent
nexus is generally not influenced by factors such as personal distress or preferences, or
by the mental ability or willingness of persons to assume responsibility for their conduct.
Accordingly, even civilians forced to directly participate in hostilities or children below
the lawful recruitment age may lose protection against direct attack.
Only in exceptional situations could the mental state of civilians call into question the
belligerent nexus of their conduct. This scenario could occur, most notably, when civilians
are totally unaware of the role they are playing in the conduct of hostilities (e.g. a driver
unaware that he is transporting a remote-controlled bomb) or when they are completely
deprived of their physical freedom of action (e.g. when they are involuntary human
shields physically coerced into providing cover in close combat). Civilians in such extreme
circumstances cannot be regarded as performing an action (i.e. as doing something) in
any meaningful sense and, therefore, remain protected against direct attack despite the
belligerent nexus of the military operation in which they are being instrumentalized.
As a result, these civilians would have to be taken into account in the proportionality
assessment during any military operation likely to inflict incidental harm on them.
c) Practical relevance of belligerent nexus

Many activities during armed conflict lack a belligerent nexus even though they cause
a considerable level of harm. For example, the exchange of fire between police and
hostage takers during an ordinary bank robbery, violent crimes committed for reasons
unrelated to the conflict, and the stealing of military equipment for private use, may
cause the required threshold of harm, but are not specifically designed to support a
party to the conflict by harming another. Similarly, the military operations of a party to
a conflict can be directly and adversely affected when roads leading to a strategically
important area are blocked by large groups of refugees or other fleeing civilians.
However, the conduct of these civilians is not specifically designed to support one
party to the conflict by causing harm to another and, therefore, lacks belligerent nexus.
This analysis would change, of course, if civilians block a road in order to facilitate the
withdrawal of insurgent forces by delaying the arrival of governmental armed forces
(or vice versa). When distinguishing between the activities that do and those that do
not amount to direct participation in hostilities, the criterion of belligerent nexus is of
particular importance in the following four situations:
Individual self-defence: The causation of harm in individual self-defence or defence
of others against violence prohibited under IHL lacks belligerent nexus. For example,
although the use of force by civilians to defend themselves against unlawful attack or
looting, rape, and murder by marauding soldiers may cause the required threshold
of harm, its purpose clearly is not to support a party to the conflict against another.
If individual self-defence against prohibited violence were to entail loss of protection
against direct attack, this would have the absurd consequence of legitimizing a
previously unlawful attack. Therefore, the use of necessary and proportionate force in
such situations cannot be regarded as direct participation in hostilities.
Exercise of power or authority over persons or territory:
IHL makes a basic distinction between the conduct of hostilities and the exercise of
power or authority over persons or territory. As a result, the infliction of death, injury,
or destruction by civilians on persons or objects that have fallen into their “hands”
or “power” within the meaning of IHL does not, without more, constitute part of the
hostilities.
28 Document No. 51
For example, the use of armed force by civilian authorities to suppress riots and other
forms of civil unrest, prevent looting, or otherwise maintain law and order in a conflict
area may cause death, injury, or destruction, but generally it would not constitute
part of the hostilities conducted between parties to an armed conflict. Likewise, once
military personnel have been captured (and, thus, are hors de combat), the suppression
of riots and prevention of escapes or the lawful execution of death sentences is not
designed to directly cause military harm to the opposing party to the conflict and,
therefore, lacks belligerent nexus.
Excluded from the concept of direct participation in hostilities is not only the lawful
exercise of administrative, judicial or disciplinary authority on behalf of a party to the
conflict, but even the perpetration of war crimes or other violations of IHL outside
the conduct of hostilities. Thus, while collective punishment, hostage-taking, and the
ill-treatment and summary execution of persons in physical custody are invariably
prohibited by IHL, they are not part of the conduct of hostilities. Such conduct may
constitute a domestic or international crime and permit the lawful use of armed force
against the perpetrators as a matter of law enforcement or defence of self or others.
Loss of protection against direct attack within the meaning of IHL, however, is not a
sanction for criminal behaviour but a consequence of military necessity in the conduct
of hostilities.
Civil unrest: During armed conflict, political demonstrations, riots, and other forms of
civil unrest are often marked by high levels of violence and are sometimes responded
to with military force. In fact, civil unrest may well result in death, injury and destruction
and, ultimately, may even benefit the general war effort of a party to the conflict by
undermining the territorial authority and control of another party through political
pressure, economic insecurity, destruction and disorder. It is therefore important to
distinguish direct participation in hostilities – which is specifically designed to support
a party to an armed conflict against another – from violent forms of civil unrest, the
primary purpose of which is to express dissatisfaction with the territorial or detaining
authorities.
Inter-civilian violence: Similarly, in order to become part of the conduct of hostilities,
use of force by civilians against other civilians, even if widespread, must be specifically
designed to support a party to an armed conflict in its military confrontation with
another. This would not be the case where civilians merely take advantage of a
breakdown of law and order to commit violent crimes. Belligerent nexus is most likely
to exist where inter-civilian violence is motivated by the same political disputes or
ethnic hatred that underlie the surrounding armed conflict and where it causes harm
of a specifically military nature.
d) Practical determination of belligerent nexus

The task of determining the belligerent nexus of an act can pose considerable practical
difficulties. For example, in many armed conflicts, gangsters and pirates operate in a
grey zone where it is difficult to distinguish hostilities from violent crime unrelated to,
or merely facilitated by, the armed conflict. These determinations must be based on the
information reasonably available to the person called on to make the determination,

but they must always be deduced from objectively verifiable factors. In practice, the
decisive question should be whether the conduct of a civilian, in conjunction with the
circumstances prevailing at the relevant time and place, can reasonably be perceived
as an act designed to support one party to the conflict by directly causing the required
threshold of harm to another party. As the determination of belligerent nexus may
lead to a civilian’s loss of protection against direct attack, all feasible precautions must
be taken to prevent erroneous or arbitrary targeting and, in situations of doubt, the
person concerned must be presumed to be protected against direct attack.
e) Summary
In order to meet the requirement of belligerent nexus, an act must be specifically
designed to directly cause the required threshold of harm in support of a party to an
armed conflict and to the detriment of another. As a general rule, harm caused (a) in
individual self-defence or defence of others against violence prohibited under IHL,
(b) in exercising power or authority over persons or territory, (c) as part of civil unrest
against such authority, or (d) during inter-civilian violence lacks the belligerent nexus
required for a qualification as direct participation in hostilities.
4. Conclusion
Applied in conjunction, the three requirements of threshold of harm, direct causation and
belligerent nexus permit a reliable distinction between activities amounting to direct
participation in hostilities and activities which, although occurring in the context of an
armed conflict, are not part of the conduct of hostilities and, therefore, do not entail
loss of protection against direct attack. Even where a specific act amounts to direct
participation in hostilities, however, the kind and degree of force used in response must
comply with the rules and principles of IHL and other applicable international law.
VI. Beginning and end of direct participation in hostilities

Measures preparatory to the execution of a specific act of direct participation in
hostilities, as well as the deployment to and the return from the location of its
execution, constitute an integral part of that act.
As civilians lose protection against direct attack “for such time” as they directly
participate in hostilities, the beginning and end of specific acts amounting to direct
participation in hostilities must be determined with utmost care. Without any doubt,
the concept of direct participation in hostilities includes the immediate execution
phase of a specific act meeting the three criteria of threshold of harm, direct causation
and belligerent nexus. It may also include measures preparatory to the execution of
such an act, as well as the deployment to and return from the location of its execution,
where they constitute an integral part of such a specific act or operation.
30 Document No. 51
1. Preparatory measures
Whether a preparatory measure amounts to direct participation in hostilities depends
on a multitude of situational factors that cannot be comprehensively described in
abstract terms. In essence, preparatory measures amounting to direct participation
in hostilities correspond to what treaty IHL describes as “military operation[s]
preparatory to an attack”. They are of a specifically military nature and so closely
linked to the subsequent execution of a specific hostile act that they already constitute
an integral part of that act. Conversely, the preparation of a general campaign of
unspecified operations would not qualify as direct participation in hostilities. In line
with the distinction between direct and indirect participation in hostilities, it could
be said that preparatory measures aiming to carry out a specific hostile act qualify as
direct participation in hostilities, whereas preparatory measures aiming to establish the
general capacity to carry out unspecified hostile acts do not.
It is neither necessary nor sufficient for a qualification as direct participation
that a preparatory measure occur immediately before (temporal proximity) or in
close geographical proximity to the execution of a specific hostile act or that it be
indispensable for its execution. For example, the loading of bombs onto an airplane
for a direct attack on military objectives in an area of hostilities constitutes a measure
preparatory to a specific hostile act and, therefore, qualifies as direct participation
in hostilities. This is the case even if the operation will not be carried out until the
next day, if the target will be selected only during the operation, and if great distance
separates the preparatory measure from the location of the subsequent attack.
Conversely, transporting bombs from a factory to an airfield storage place and then
to an airplane for shipment to another storehouse in the conflict zone for unspecified
use in the future would constitute a general preparatory measure qualifying as mere
indirect participation.
Similarly, if carried out with a view to the execution of a specific hostile act, all of the
following would almost certainly constitute preparatory measures amounting to
direct participation in hostilities: equipment, instruction, and transport of personnel;
gathering of intelligence; and preparation, transport, and positioning of weapons and
equipment. Examples of general preparation not entailing loss of protection against
direct attack would commonly include purchase, production, smuggling and hiding of
weapons; general recruitment and training of personnel; and financial, administrative
or political support to armed actors. It should be reiterated that these examples can
only illustrate the principles based on which the necessary distinctions ought to be
made and cannot replace a careful assessment of the totality of the circumstances
prevailing in the concrete context and at the time and place of action.
2. Deployment and return

Where the execution of a specific act of direct participation in hostilities requires prior
geographic deployment, such deployment already constitutes an integral part of
the act in question. Likewise, as long as the return from the execution of a hostile act
remains an integral part of the preceding operation, it constitutes a military withdrawal
and should not be confused with surrender or otherwise becoming hors de combat.
A deployment amounting to direct participation in hostilities begins only once the

deploying individual undertakes a physical displacement with a view to carrying out
a specific operation. The return from the execution of a specific hostile act ends once
the individual in question has physically separated from the operation, for example by
laying down, storing or hiding the weapons or other equipment used and resuming
activities distinct from that operation.
Whether a particular individual is engaged in deployment to or return from the
execution of a specific hostile act depends on a multitude of situational factors, which
cannot be comprehensively described in abstract terms. The decisive criterion is that
both the deployment and return be carried out as an integral part of a specific act
amounting to direct participation in hostilities. That determination must be made with
utmost care and based on a reasonable evaluation of the prevailing circumstances.
Where the execution of a hostile act does not require geographic displacement, as may
be the case with computer network attacks or remote-controlled weapons systems,
the duration of direct participation in hostilities will be restricted to the immediate
execution of the act and preparatory measures forming an integral part of that act.
3. Conclusion
Where preparatory measures and geographical deployments or withdrawals constitute
an integral part of a specific act or operation amounting to direct participation in
hostilities, they extend the beginning and end of the act or operation beyond the
phase of its immediate execution.
C. MODALITIES GOVERNING THE LOSS OF PROTECTION

Under customary and treaty IHL, civilians lose protection against direct attack either
by directly participating in hostilities or by ceasing to be civilians altogether, namely
by becoming members of State armed forces or organized armed groups belonging
to a party to an armed conflict. In view of the serious consequences for the individuals
concerned, the present chapter endeavours to clarify the precise modalities that govern
such loss of protection under IHL. The following sections examine the temporal scope
of the loss of protection against direct attack (VII), the precautions and presumptions
in situations of doubt (VIII), the rules and principles governing the use of force against
legitimate military targets (IX), and the consequences of regaining protection against
direct attack (X).
In line with the aim of the Interpretive Guidance, this chapter will focus on examining
loss of protection primarily in case of direct participation in hostilities (civilians), but
also in case of continuous combat function (members of organized armed groups),
as the latter concept is intrinsically linked to the concept of direct participation
in hostilities. It will not, or only marginally, address the loss of protection in case of
membership in State armed forces, which largely depends on criteria unrelated to
direct participation in hostilities, such as formal recruitment, incorporation, discharge
or retirement under domestic law. Subject to contrary provisions of IHL, this does
32 Document No. 51
not exclude the applicability of the conclusions reached in Sections VII to X, mutatis
mutandis, to members of State armed forces as well.
VII. Temporal scope of the loss of protection

Civilians lose protection against direct attack for the duration of each specific act
amounting to direct participation in hostilities, whereas members of organized
armed groups belonging to a non-State party to an armed conflict cease to be
civilians (see above II), and lose protection against direct attack, for as long as
they assume their continuous combat function.
1. Civilians
According to treaty and customary IHL applicable in international and non-international
armed conflict, civilians enjoy protection against direct attack “unless and for such time”
as they take a direct part in hostilities. Civilians directly participating in hostilities do
not cease to be part of the civilian population, but their protection against direct attack
is temporarily suspended. The phrase “unless and for such time” clarifies that such
suspension of protection lasts exactly as long as the corresponding civilian engagement
in direct participation in hostilities. This necessarily entails that civilians lose and regain
protection against direct attack in parallel with the intervals of their engagement in
direct participation in hostilities (so-called “revolving door” of civilian protection).
The revolving door of civilian protection is an integral part, not a malfunction, of IHL.
It prevents attacks on civilians who do not, at the time, represent a military threat.
In contrast to members of organized armed groups, whose continuous function it is
to conduct hostilities on behalf of a party to the conflict, the behaviour of individual
civilians depends on a multitude of constantly changing circumstances and, therefore,
is very difficult to anticipate. Even the fact that a civilian has repeatedly taken a direct
part in hostilities, either voluntarily or under pressure, does not allow a reliable
prediction as to future conduct. As the concept of direct participation in hostilities
refers to specific hostile acts, IHL restores the civilian’s protection against direct attack
each time his or her engagement in a hostile act ends. Until the civilian in question
again engages in a specific act of direct participation in hostilities, the use of force
against him or her must comply with the standards of law enforcement or individual
self-defence.
Although the mechanism of the revolving door of protection may make it more difficult
for the opposing armed forces or organized armed groups to respond effectively
to the direct participation of civilians in hostilities, it remains necessary to protect
the civilian population from erroneous or arbitrary attack and must be acceptable
for the operating forces or groups as long as such participation occurs on a merely
spontaneous, unorganized or sporadic basis.
2. Members of organized armed groups

Members of organized armed groups belonging to a non-State party to the conflict
cease to be civilians for as long as they remain members by virtue of their continuous
combat function. Formally, therefore, they no longer benefit from the protection
provided to civilians “unless and for such time” as they take a direct part in hostilities.
Indeed, the restriction of loss of protection to the duration of specific hostile acts was
designed to respond to spontaneous, sporadic or unorganized hostile acts by civilians
and cannot be applied to organized armed groups. It would provide members of
such groups with a significant operational advantage over members of State armed
forces, who can be attacked on a continuous basis. This imbalance would encourage
organized armed groups to operate as farmers by day and fighters by night. In the long
run, the confidence of the disadvantaged party in the capability of IHL to regulate the
conduct of hostilities satisfactorily would be undermined, with serious consequences
ranging from excessively liberal interpretations of IHL to outright disrespect for the
protections it affords.
Instead, where individuals go beyond spontaneous, sporadic, or unorganized direct
participation in hostilities and become members of an organized armed group
belonging to a party to the conflict, IHL deprives them of protection against direct
attack for as long as they remain members of that group. In other words, the “revolving
door” of protection starts to operate based on membership. As stated earlier,
membership in an organized armed group begins in the moment when a civilian
starts de facto to assume a continuous combat function for the group, and lasts until
he or she ceases to assume such function. Disengagement from an organized armed
group need not be openly declared; it can also be expressed through conclusive
behaviour, such as a lasting physical distancing from the group and reintegration into
civilian life or the permanent resumption of an exclusively non-combat function (e.g.,
political or administrative activities). In practice, assumption of, or disengagement
from, a continuous combat function depends on criteria that may vary with the
political, cultural, and military context. That determination must therefore be made
in good faith and based on a reasonable assessment of the prevailing circumstances,
presuming entitlement to civilian protection in case of doubt.
3. Conclusion
Under customary and treaty IHL, civilians directly participating in hostilities, as well
as persons assuming a continuous combat function for an organized armed group
belonging to a party to the conflict lose their entitlement to protection against
direct attack. As far as the temporal scope of the loss of protection is concerned, a
clear distinction must be made between civilians and organized armed actors. While
civilians lose their protection for the duration of each specific act amounting to direct
participation in hostilities, members of organized armed groups belonging to a party
to the conflict are no longer civilians and, therefore, lose protection against direct
attack for the duration of their membership, that is to say, for as long as they assume
their continuous combat function.
VIII. Precautions and presumptions in situations of doubt

All feasible precautions must be taken in determining whether a person is a
civilian and, if so, whether that civilian is directly participating in hostilities.
34 Document No. 51
In case of doubt, the person must be presumed to be protected against direct

attack.
One of the main practical problems caused by various degrees of civilian participation
in hostilities is that of doubt as to the identity of the adversary. For example, in
many counterinsurgency operations, armed forces are constantly confronted with
individuals adopting a more or less hostile attitude. The difficulty for such forces is
to distinguish reliably between members of organized armed groups belonging to
an opposing party to the conflict, civilians directly participating in hostilities on a
spontaneous, sporadic, or unorganized basis, and civilians who may or may not be
providing support to the adversary, but who do not, at the time, directly participate
in hostilities. To avoid the erroneous or arbitrary targeting of civilians entitled to
protection against direct attack, there must be clarity as to the precautions to be taken
and the presumptions to be observed in situations of doubt.
1. The requirement of feasible precautions

Prior to any attack, all feasible precautions must be taken to verify that targeted
persons are legitimate military targets. Once an attack has commenced, those
responsible must cancel or suspend the attack if it becomes apparent that the target is
not a legitimate military target. Before and during any attack, everything feasible must
be done to determine whether the targeted person is a civilian and, if so, whether he
or she is directly participating in hostilities.
As soon as it becomes apparent that the targeted person is entitled to civilian protection,
those responsible must refrain from launching the attack, or cancel or suspend it if it
is already underway. This determination must be made in good faith and in view of
all information that can be said to be reasonably available in the specific situation. As
stated in treaty IHL, “[f]easible precautions are those precautions which are practicable
or practically possible taking into account all circumstances ruling at the time, including
humanitarian and military considerations”. In addition, a direct attack against a civilian
must be cancelled or suspended if he or she becomes hors de combat.
2. Presumption of civilian protection

For the purposes of the principle of distinction, IHL distinguishes between two generic
categories of persons: civilians and members of the armed forces of the parties to the
conflict. Members of State armed forces (except medical and religious personnel) or
organized armed groups are generally regarded as legitimate military targets unless they
surrender or otherwise become hors de combat. Civilians are generally protected against
direct attack unless and for such time as they directly participate in hostilities. For each
category, the general rule applies until the requirements for an exception are fulfilled.
Consequently, in case of doubt as to whether a specific civilian conduct qualifies as
direct participation in hostilities, it must be presumed that the general rule of civilian
protection applies and that this conduct does not amount to direct participation in
hostilities. The presumption of civilian protection applies, a fortiori, in case of doubt as
to whether a person has become a member of an organized armed group belonging
to a party to the conflict. Obviously, the standard of doubt applicable to targeting

decisions cannot be compared to the strict standard of doubt applicable in criminal
proceedings but rather must reflect the level of certainty that can reasonably be
achieved in the circumstances. In practice, this determination will have to take into
account, inter alia, the intelligence available to the decision maker, the urgency of
the situation, and the harm likely to result to the operating forces or to persons and
objects protected against direct attack from an erroneous decision.
The presumption of civilian protection does not exclude the use of armed force against
civilians whose conduct poses a grave threat to public security, law and order without
clearly amounting to direct participation in hostilities. In such cases, however, the use
of force must be governed by the standards of law enforcement and of individual
self-defence, taking into account the threat to be addressed and the nature of the
surrounding circumstances.
3. Conclusion
In practice, civilian direct participation in hostilities is likely to entail significant confusion
and uncertainty in the implementation of the principle of distinction. In order to avoid
the erroneous or arbitrary targeting of civilians entitled to protection against direct
attack, it is therefore of particular importance that all feasible precautions be taken
in determining whether a person is a civilian and, if so, whether he or she is directly
participating in hostilities. In case of doubt, the person in question must be presumed
to be protected against direct attack.
IX. Restraints on the use of force in direct attack

In addition to the restraints imposed by international humanitarian law on
specific means and methods of warfare, and without prejudice to further
restrictions that may arise under other applicable branches of international law,
the kind and degree of force which is permissible against persons not entitled
to protection against direct attack must not exceed what is actually necessary to
accomplish a legitimate military purpose in the prevailing circumstances.
Loss of protection against direct attack, whether due to direct participation in hostilities
(civilians) or continuous combat function (members of organized armed groups), does
not mean that the persons concerned fall outside the law. It is a fundamental principle of
customary and treaty IHL that “[t]he right of belligerents to adopt means of injuring the
enemy is not unlimited”. Indeed, even direct attacks against legitimate military targets are
subject to legal constraints, whether based on specific provisions of IHL, on the principles
underlying IHL as a whole, or on other applicable branches of international law.
1. Prohibitions and restrictions laid down in specific provisions of IHL

Any military operation carried out in a situation of armed conflict must comply
with the applicable provisions of customary and treaty IHL governing the conduct
of hostilities. These include the rules derived from the principles of distinction,
precaution, and proportionality, as well as the prohibitions of denial of quarter and
36 Document No. 51
perfidy. They also include the restriction or prohibition of selected weapons and the
prohibition of means and methods of warfare of a nature to cause superfluous injury
or unnecessary suffering (maux superflus). Apart from the prohibition or restriction
of certain means and methods of warfare, however, the specific provisions of IHL do
not expressly regulate the kind and degree of force permissible against legitimate
military targets. Instead, IHL simply refrains from providing certain categories of
persons, including civilians directly participating in hostilities, with protection from
direct “attacks”, that is to say, from “acts of violence against the adversary, whether
in offence or in defence”. Clearly, the fact that a particular category of persons is not
protected against offensive or defensive acts of violence is not equivalent to a legal
entitlement to kill such persons without further considerations. At the same time, the
absence of an unfettered “right” to kill does not necessarily imply a legal obligation to
capture rather than kill regardless of the circumstances.
2. The principles of military necessity and humanity

In the absence of express regulation, the kind and degree of force permissible in
attacks against legitimate military targets should be determined, first of all, based on
the fundamental principles of military necessity and humanity, which underlie and
inform the entire normative framework of IHL and, therefore, shape the context in
which its rules must be interpreted. Considerations of military necessity and humanity
neither derogate from nor override the specific provisions of IHL, but constitute
guiding principles for the interpretation of the rights and duties of belligerents within
the parameters set by these provisions.
Today, the principle of military necessity is generally recognized to permit “only that
degree and kind of force, not otherwise prohibited by the law of armed conflict, that
is required in order to achieve the legitimate purpose of the conflict, namely the
complete or partial submission of the enemy at the earliest possible moment with
the minimum expenditure of life and resources”. Complementing and implicit in the
principle of military necessity is the principle of humanity, which “forbids the infliction
of suffering, injury or destruction not actually necessary for the accomplishment of
legitimate military purposes”. In conjunction, the principles of military necessity and of
humanity reduce the sum total of permissible military action from that which IHL does
not expressly prohibit to that which is actually necessary for the accomplishment of a
legitimate military purpose in the prevailing circumstances.
While it is impossible to determine, ex ante, the precise amount of force to be used in
each situation, considerations of humanity require that, within the parameters set by
the specific provisions of IHL, no more death, injury, or destruction be caused than
is actually necessary for the accomplishment of a legitimate military purpose in the
prevailing circumstances. What kind and degree of force can be regarded as necessary
in an attack against a particular military target involves a complex assessment based
on a wide variety of operational and contextual circumstances. The aim cannot be to
replace the judgment of the military commander by inflexible or unrealistic standards;
rather it is to avoid error, arbitrariness, and abuse by providing guiding principles for the
choice of means and methods of warfare based on his or her assessment of the situation.
In classic large-scale confrontations between well-equipped and organized armed

forces or groups, the principles of military necessity and of humanity are unlikely to
restrict the use of force against legitimate military targets beyond what is already
required by specific provisions of IHL. The practical importance of their restraining
function will increase with the ability of a party to the conflict to control the
circumstances and area in which its military operations are conducted, and may
become decisive where armed forces operate against selected individuals in situations
comparable to peacetime policing. In practice, such considerations are likely to
become particularly relevant where a party to the conflict exercises effective territorial
control, most notably in occupied territories and non-international armed conflicts.
For example, an unarmed civilian sitting in a restaurant using a radio or mobile phone
to transmit tactical targeting intelligence to an attacking air force would probably have
to be regarded as directly participating in hostilities. Should the restaurant in question
be situated within an area firmly controlled by the opposing party, however, it may
be possible to neutralize the military threat posed by that civilian through capture
or other non-lethal means without additional risk to the operating forces or the
surrounding civilian population. Similarly, under IHL, an insurgent military commander
of an organized armed group would not regain civilian protection against direct
attack simply because he temporarily discarded his weapons, uniform and distinctive
signs in order to visit relatives inside government-controlled territory. Nevertheless,
depending on the circumstances, the armed or police forces of the government may
be able to capture that commander without resorting to lethal force. Further, large
numbers of unarmed civilians who deliberately gather on a bridge in order to prevent
the passage of governmental ground forces in pursuit of an insurgent group would
probably have to be regarded as directly participating in hostilities. In most cases,
however, it would be reasonably possible for the armed forces to remove the physical
obstacle posed by these civilians through means less harmful than a direct military
attack on them.
In sum, while operating forces can hardly be required to take additional risks for
themselves or the civilian population in order to capture an armed adversary alive, it
would defy basic notions of humanity to kill an adversary or to refrain from giving him
or her an opportunity to surrender where there manifestly is no necessity for the use
of lethal force. In such situations, the principles of military necessity and of humanity
play an important role in determining the kind and degree of permissible force against
legitimate military targets. Lastly, although this Interpretive Guidance concerns the
analysis and interpretation of IHL only, its conclusions remain without prejudice to
additional restrictions on the use of force, which may arise under other applicable
frameworks of international law such as, most notably, international human rights law
or the law governing the use of interstate force (jus ad bellum).
3. Conclusion
In situations of armed conflict, even the use of force against persons not entitled to
protection against direct attack remains subject to legal constraints. In addition to the
restraints imposed by IHL on specific means and methods of warfare, and without
38 Document No. 51
prejudice to further restrictions that may arise under other applicable branches of
international law, the kind and degree of force which is permissible against persons
not entitled to protection against direct attack must not exceed what is actually
necessary to accomplish a legitimate military purpose in the prevailing circumstances.
X. Consequences of regaining civilian protection

International humanitarian law neither prohibits nor privileges civilian direct
participation in hostilities. When civilians cease to directly participate in
hostilities, or when members of organized armed groups belonging to a non-
State party to an armed conflict cease to assume their continuous combat
function, they regain full civilian protection against direct attack, but are not
exempted from prosecution for violations of domestic and international law
they may have committed.
1. Lack of immunity from domestic prosecution

IHL provides an express “right” to directly participate in hostilities only for members of
the armed forces of parties to international armed conflicts and participants in a levée
en masse. This right does not imply an entitlement to carry out acts prohibited under
IHL, but merely provides combatants with immunity from domestic prosecution
for acts which, although in accordance with IHL, may constitute crimes under the
national criminal law of the parties to the conflict (the so-called combatant privilege).
The absence in IHL of an express right for civilians to directly participate in hostilities
does not necessarily imply an international prohibition of such participation. Indeed,
as such, civilian direct participation in hostilities is neither prohibited by IHL nor
criminalized under the statutes of any prior or current international criminal tribunal
or court. However, because civilians – including those entitled to prisoner of war status
under Article 4 [4] and [5] GC III – are not entitled to the combatant privilege, they
do not enjoy immunity from domestic prosecution for lawful acts of war, that is, for
having directly participated in hostilities while respecting IHL. Consequently, civilians
who have directly participated in hostilities and members of organized armed groups
belonging to a non-State party to a conflict may be prosecuted and punished to the
extent that their activities, their membership, or the harm caused by them is penalized
under national law (e.g., as treason, arson, murder, etc.).
2. Obligation to respect international humanitarian law

The case law of international military tribunals that followed the Second World War,
the ICTY and the ICTR consistently affirms that even individual civilians can violate
provisions of IHL and commit war crimes. It is the character of the acts and their nexus
to the conflict, not the status of the perpetrator, that are decisive for their relevance
under IHL. There can be no doubt that civilians directly participating in hostilities must
respect the rules of IHL, including those on the conduct of hostilities, and may be held
responsible for war crimes just like members of State armed forces or organized armed
groups. For example, it would violate IHL for civilians to direct hostile acts against
persons and objects protected against direct attack, to deny quarter to adversaries
who are hors de combat, or to capture, injure or kill an adversary by resort to perfidy.
In practice, the prohibition on perfidy is of particular interest, as civilians directly
participating in hostilities often do not carry arms openly or otherwise distinguish
themselves from the civilian population. When civilians capture, injure, or kill an
adversary and in doing so they fail to distinguish themselves from the civilian
population in order to lead the adversary to believe that they are entitled to civilian
protection against direct attack, this may amount to perfidy in violation of customary
and treaty IHL.
3. Conclusion
In the final analysis, IHL neither prohibits nor privileges civilian direct participation
in hostilities. Therefore, when civilians cease to directly participate in hostilities, or
when individuals cease to be members of organized armed groups because they
disengage from their continuous combat function, they regain full civilian protection
against direct attack. However, in the absence of combatant privilege, they are not
exempted from prosecution under national criminal law for acts committed during
their direct participation or membership. Moreover, just like members of State armed
forces or organized armed groups belonging to the parties to an armed conflict,
civilians directly participating in hostilities must respect the rules of IHL governing
the conduct of hostilities and may be held individually responsible for war crimes and
other violations of international criminal law.

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Part II – Direct Participation in Hostilities 1

Document No. 51, ICRC, Interpretive Guidance

1. Purpose and nature of the Interpretive Guidance

2. The issue of civilian participation in hostilities

3. Key legal questions

Part 1: RECOMMENDATIONS OF THE ICRC

I. The concept of civilian in international armed conflict

II. The concept of civilian in non-international armed conflict

III. Private contractors and civilian employees

IV. Direct participation in hostilities as a specific act

V. Constitutive elements of direct participation in hostilities

destruction on persons or objects protected against direct attack (threshold of

VI. Beginning and end of direct participation in hostilities

VII. Temporal scope of the loss of protection

VIII. Precautions and presumptions in situations of doubt

IX. Restraints on the use of force in direct attack

X. Consequences of regaining civilian protection

Part 2: RECOMMENDATIONS AND COMMENTARY

A. THE CONCEPT OF CIVILIAN

I. The concept of civilian in international armed conflict

1. Mutual exclusiveness of the concepts of civilian, armed forces and levée en

b) Meaning and significance of “belonging to” a party to the conflict

II. The concept of civilian in non-international armed conflict

1. Mutual exclusiveness of the concepts of civilian, armed forces and organized

parties to the conflict are mutually exclusive categories also in non-international

b) Article 3 common to the Geneva Conventions

a non-international armed conflict are referred to as “State armed forces”, whereas

2. State armed forces

3. Organized armed groups

spontaneous, sporadic, or unorganized basis, or who assume exclusively political,

III. Private contractors and civilian employees

1. Particular difficulties related to private contractors and civilian employees

2. International armed conflict

3. Non-international armed conflict

B. THE CONCEPT OF DIRECT PARTICIPATION IN HOSTILITIES

IV. Direct participation in hostilities as a specific act

1. Basic components of the notion of direct participation in hostilities

2. Restriction to specific acts

V. Constitutive elements of direct participation in hostilities

a) Adversely affecting the military operations or military capacity of a party to

b) Inflicting death, injury or destruction on persons or objects protected against

a) Conduct of hostilities, general war effort, and war sustaining activities

in hostilities. Some of these activities may even be indispensable to harming the

b) Direct and indirect causation

c) Direct causation in collective operations

d) Causal, temporal, and geographic proximity

an integral part of ongoing combat operations and, therefore, as direct participation

b) Belligerent nexus and subjective intent

c) Practical relevance of belligerent nexus

d) Practical determination of belligerent nexus

information reasonably available to the person called on to make the determination,

VI. Beginning and end of direct participation in hostilities

2. Deployment and return

A deployment amounting to direct participation in hostilities begins only once the

C. MODALITIES GOVERNING THE LOSS OF PROTECTION

VII. Temporal scope of the loss of protection

2. Members of organized armed groups

VIII. Precautions and presumptions in situations of doubt

Part II – Direct Participation in Hostilities 1