Undersecretary of the Navy Theodore Roosevelt resigns to form a volunteer militia unit called "The Rough Riders" to fight in the Spanish-American War.Undersecretary of the Navy Theodore Roosevelt resigns to form a volunteer militia unit called "The Rough Riders" to fight in the Spanish-American War.Undersecretary of the Navy Theodore Roosevelt resigns to form a volunteer militia unit called "The Rough Riders" to fight in the Spanish-American War.