This essay argues that the roots of successful Islamist political mobilization in new democracies lie in the developmental trajectories of the authoritarian regimes that preceded them. Tunisia under Ben Ali and Egypt under Mubarak, where Islamists flourished in opposition, are examples of corrupted development, in which the failure of a secular regime to provide widely shared increases in material prosperity facilitated mass opposition to authoritarian rule under various forms of Islamism. Indonesia under Suharto represents corrupt development, in which sustained improvements in material welfare hamstrung the ability of a nascent Islamist opposition to develop a broad movement base. These differences in the breadth of opposition to incumbent authoritarian regimes, in turn, explain the failure of Islamism as an electoral force in Indonesia, and its success in Tunisia and Egypt.