How can we understand the origins and resilience of Colombia’s long-running insurgency? A leading theory emphasizes the feasibility of insurgency, identifying drug trafficking as the main culprit. I propose an alternative theory of civil violence that emphasizes how bargaining over property rights in the face of deep vertical inequality deepens the subordinate group’s social identity, heightens its sense of grievance, and facilitates collective violence. An examination of the history of land reform struggles in Colombia echoes this pattern. Struggles over land reforms in the 1920s and 1930s created new patterns of collective action that helped sustain campesino groups in the “independent republics” of the 1950s and 1960s and the creation of the FARC in 1964. This analysis suggests that the Colombian state’s lack of credibility on issues of land reform demands a significant third-party enforcement of any peace agreement and confidence-building measures between the FARC and the Colombian government.