Although most humanitarians advocate more international intervention in Darfur, some analysts urge the opposite on grounds that intervention has backfired due to the problem of moral hazard. These contrarians argue that the expectation of benefiting from intervention is what emboldens Darfur’s rebels to fight, which provokes state-sponsored retaliation against their perceived civilian supporters, thereby exacerbating and prolonging the humanitarian emergency. This article tests the moralhazard hypothesis against four other potential explanations for why Darfur’s militants launched and perpetuated their rebellion despite being unable to protect their civilians from genocidal retaliation. The evidence indicates that moral hazard—the expectation of humanitarian intervention—increased both the magnitude and duration of Darfur’s rebellion, and therefore the retaliation it provoked against civilians. Competing hypotheses are less plausible but cannot be ruled out completely based on available evidence. The article explores the policy implications for intervention in Darfur and other humanitarian emergencies, and offers suggestions for further research.