The importance of concurrence: The impact of bicameralism on government formation and duration

Recent research on parliamentary government demonstrates that institutions critically affect government formation and survival. Yet, surprisingly, virtually no work has explored the impact of bicameralism on coalitional politics, despite a burgeoning interest in the study of bicameral legislatures. Cabinet survival almost never depends on formal upper-chamber approval, but bicameralism does fundamentally shape policy outcomes. Therefore, coalition builders in bicameral systems might seek to obtain concurrent majorities in both chambers, to ensure that government policies pass into law. And governments with upper-chamber majority support should survive longer than those without, Examining data from 202 governments in ten countries, we find little evidence of bicameral effects on government formation, but strong support for the duration hypothesis-governments with upper-chamber majorities last substantially longer than those without. These results hold even in the face of variation in the constitutional powers and ideological compositions of upper chambers. Work on parliamentary government can no longer ignore the larger institutional context of bicameralism.