Where statehood is contested, questions of identity and territory define the political landscape. Despite maintaining de facto sovereignty, states like Taiwan find themselves unrecognized in today’s international system because another power claims the state as part of their territory. This fraught status, in turn, significantly affects the domestic politics of these places. Lev Nachman’s exploration of Taiwan’s political landscape after the 2014 Sunflower Movement brings a fresh perspective to understanding social movement mobilization and political party formation in what he terms “contested states.” In these states, political cleavages are defined not by traditional left-right issues but by questions of identity, territory, and what to do about the country that claims them. Drawing from 150 interviews with Taiwanese activists and politicians, as well as a comparative analysis of Ukraine, Nachman reveals that traditional political science theories fall short when explaining the formation of movement parties in such contexts. Instead, he argues, looming existential threats and strained relationships between activists and established proindependence parties drive social movements into formal political arenas. Contested Taiwan offers a new approach to understanding contested statehood, movement party formation, and what motivates individuals to take political action across the world.