This article uses the recent nuclear freeze movement as a vehicle for analyzing the ways in which United States political institutions cope with dissident movements. Building on the literature on political opportunity structure, I argue that United States political institutions reflect James Madison's strategy for coping with dissent by fragmenting political power. The Madisonian structure of United States government, by providing relatively easy institutional access to some challengers and numerous venues for often ritualized participation, serves to fragment, coopt, and dissipate dissident movements. I identify three complementary components of the process of fragmentation and dissipation: marginalization, depoliticization, and institutionalization. I then examine the political implications of institutionalization in the case of the nuclear freeze movement with a discussion of the movement's influence on policy. I conclude with a call for more comparative research on the process and political impact of institutionalizing social protest movements.