Abstract: We extend models of policymaking within formal institutions to include in the action set of players alternative political actions (such as road blockades). There are various self-reinforcing mechanisms in the choice of venues and styles for political participation, leading to multiple equilibria. Polities in more institutionalized equilibria will behave as predicted in the “tidy” literature on political institutions and policies. Polities in less institutionalized equilibria might behave differently, with important implications for cross national empirical analysis of the effects of formal political rules on public policy. We derive a number of comparative statics results. For instance, lower institutionalization is more likely, the more asymmetric the distribution of de jure political power. Three levels of empirical evidence support our argument: cross-country correlations, survey responses for 18 Latin American countries, and a narrative of the case of a switch from a more to a less institutionalized equilibrium in Bolivia.