Nationalist conflict has been one of the most pervasive and intractable types of conflict in the modern era. In some places, nationalist conflict has entailed lengthy wars, terrorist campaigns, and rural insurgency. Yet in many others, nationalist organizations have pursued peaceful strategies, engaging in bargaining, diplomacy, and popular protest. Why do some nationalist movements turn violent, whereas others remain primarily peaceful? Drawing on nationalist struggles against the French colonial empire, the competitive violence theory posits that violence was primarily driven by competition among nationalists. Nationalist violence erupted when colonial states pursued policies to restrict nationalist opposition and repress leading nationalists, creating a leadership vacuum and encouraging new nationalist actors to use violence to vie for influence. The competitive violence theory exemplifies an approach that can explain variation in both the timing and location of violence.