Zero Dark Thirty is a procedural CIA-based thriller in the mould of TV's Homeland. This film, however, is based on real-life events, so it doesn't have the benefit of being able to withhold in the way Homeland's first series did with Twin Peaks-like delectation. What Zero Dark Thirty does have is a narrative based on first-hand accounts, and it makes no explicit judgement about the content of those accounts. We simply get to see what (apparently) happened during the manhunt for "UBJ".
The film's lack of polemic is both a blessing a curse. It's a blessing because it's rare that a film dealing with such volatile subject matter is depicted procedurally. Usually when a narrative is made ostensibly apolitical it's as a result of an unconvincing moral rebalancing, where the filmmakers go to great lengths to present both sides fairly. But Mark Boal and Kathryn Bigelow's disinterest is also a curse because, in avoiding judgement, it surreptitiously falls firmly on the side of the CIA. It shows what it's allowed to show, but keeps their secrets ("undisclosed location" and all that); and it portrays the operatives as the honourable front-liners getting their hands dirty (but not bloody), beyond moral reproach by virtue of hard graft. In Bigelow's world, it's the suits in Washington who have the blood in their hands - they're disconnected, as evidenced when torture-specialist Dan (Jason Clarke) returns to US headquarters from the field and loses his nerve, becoming a man of soft probabilities.
Clarke is solid but lost amidst superior talent, as he was in John Hillcoat's recent Lawless. Jessica Chastain delivers a nuanced performance. Driven professionals in films often come across as stolid, but Chastain is an actor of subtlety - even if Bigelow can't help lensing her like a wind-swept movie star in the Middle Eastern magic light. Jennifer Ehle uses her moon-faced radiance to good effect, filling her eager operative Jessica with youthful energy. There's a fair amount of distracting spot-the-cameo going on, particularly toward the end, when Joel Edgerton, Mark Duplass and James Gandolfini turn up.
Bigelow's directorial talent is never in doubt. The final sequence in particular is harrowingly tense, even though we know the outcome. And she generally gets the best out of actors. But make no mistake: this is a deeply patriotic film which is cheering for the home team, and it does so under the guise of objectivity, which makes it more manipulative than flag-waving fare like Last Ounce of Courage or Act of Valor, albeit much more skilfully made.