In June 23, 2016, voters in the United Kingdom have just approved a referendum calling for leaving the European Union. The case describes the motives for European integration, the rise of separatist movements in the United Kingdom and elsewhere, and the referendum process itself. The purpose of this case is to provide a contemporary counterpoint to a discussion of the economic and political motivations for the American Civil War. Dominant themes highlighted here are economic nationalism, political nationalism, cultural centrism and ethnocentrism, and populism.