Revolutionary protest rarely begins life as democratic or revolutionary. Instead, it grows in a process of positive feedback, incorporating new constituencies and generating new demands. If protest is not revolutionary at its onset, theory should reflect this and be able to explain the endogenous emergence of democratic demands. In this article, I combine multiple data sources on the 2010-11 Tunisian Revolution, including survey data, an original event catalogue, and field interviews. I show that the correlates of protest occurrence and participation change significantly during the uprising. Using the Tunisian case as a theory-building exercise, I argue that the formation of protest coalitions is essential, rather than incidental, to democratic revolution.