Recent world events have renewed interest among social movement scholars in strategies and associated outcomes in campaigns against nondemocratic regimes. Most comparative work is limited to large-scale mobilization and takes violent/nonviolent tactics as given, thereby overlooking prior group mobilization and initial tactic choice. While a chosen tactic is plausibly related to group characteristics and resources, we argue that the mobilization process underlying large-scale campaigns begins when groups stake claims and assess those claims' potential. The proposed framework can help to explain both the specific tactics chosen and whether campaigns take on violent or nonviolent forms. We focus on grievances and the origins of mobilization through formulation of claims-making disputes over regime type, government composition, and electoral legitimacy - independent of mobilization - and consider how resources provide a comparative advantage for violence or nonviolence. An application to states in the former Soviet Union demonstrates the framework's utility for understanding when claims evolve to violent and nonviolent mobilization.