This article examines the link between citizens' partisanship and the institutional context that constrains potential policy changes. Combining institutional and behavioral theories, I argue that as the institutional constraints on policy change increase, the political party in power is less likely to matter in determining policy outcomes, and therefore individuals are less likely to become partisans. I confirm this systematic relationship using multilevel
analyses of the ANES data from 1964 to 2008 and the CSES data that covers 114 surveys across 49 countries. This approach enables us to explain the patterns of partisanship across diverse political contexts in a consistent way, regardless of the level of their institutional complexity. In contrast to existing studies, my results also suggest that party polarization can lead to the decline of mass partisanship as a result of its interplay with institutional
configurations and subsequent policy gridlock.
