Who Rules? Support Coalitions and Regime Survival, 1789–2020

All political regimes rely on coalitions of supporters to govern and remain in power. We discuss, specify, and test arguments pertaining to how the numerical size as well as social diversity of regime support coalitions influence regime longevity. We use recently collected data on support coalition characteristics, with global coverage and time series exceeding 230 years, and find that larger as well as more diverse regime support coalitions are positively related to regime longevity. Both patterns hold up in different time periods and in sub-samples including only autocratic regimes. We also discuss and find indications that increased coalition size may limit certain types of regime breakdown (e.g., from popular uprisings) but not others (e.g., coups). Coalition diversity is negatively related to different types of regime breakdown, and these patterns may reflect that diverse coalitions offer regimes access to variegated power resources that enable them to mitigate different threats.