My dissertation, “The Dark Side of the Band of Brothers: Explaining Unit Participation in War Crimes,” explores how states internally comply with international legal obligations, specifically how states ensure that their soldiers abide by customary laws of war. I ask why some units participate in war crimes when other units facing similar circumstances do not. I test three explanations: military socialization, civilian influence, and unit subculture. First, I test whether the military both adequately instructs soldiers about the laws of war and consistently punishes soldiers who violate them. Second, I look at the role of civilian leaders; policy-makers may exaggerate the nature of the conflict or dehumanize the enemy, and this rhetoric may persuade units that the laws of war do not apply. Third, I examine unit subcultures. If a unit’s culture challenges the norms of the larger organization, this counter-culture may encourage the unit to reject organizational restrictions, use excessive force, and participate in war crimes.