Political Norms

Abstract

Recent political developments around the world have focused attention on the fraying of political norms, often understood as informal restraints on opportunistic behavior. This paper presents a theory of political norms that incorporates both ideology and institutional structure. In the model, an election determines which party holds office in each period over an infinite horizon. Each period presents the majority party with an opportunity to modify a status quo policy, but its ability to do so is limited by informal norms and formal institutional barriers. We show that greater institutional constraints do not necessarily make norms more sustainable, and that norms may be asymmetric in electorally imbalanced settings. Under optimal norms, increasing ideological polarization makes norms easier to uphold, while also reducing welfare. Finally, norms upheld by minority parties are less sustainable in equilibrium, and voter optimal norms require minority concessions to achieve greater electoral competitiveness.