This book tests a new approach to understanding ethnic mobilization and considers the interplay of global forces, national-level variation in inequality and repression, and political mobilization of ethnicity. It advances the claim that economic and political integration among the world's states increases the influence of ethnic identity in political movements. Drawing on a 100-country dataset analyzing ethnic events and rebellions from 1965 to 1998, Olzak shows that to the degree in which a country participates in international social movement organizations, ethnic identities in that country become more salient. International organizations spread principles of human rights, anti-discrimination, sovereignty, and self-determination. At the local level, poverty and restrictions on political rights then channel group demands into ethnic mobilization. This study will be of great importance to scholars and policy makers seeking new and powerful explanations for understanding why some conflicts turn violent while others do not.