Crisis at Home, Exit Abroad: Coups, Civil Wars, and Coalition Defection

Why do states prematurely withdraw from multinational military operations? While existing explanations emphasize domestic politics, coalition dynamics, and battlefield conditions, this article identifies leadership insecurity as a key driver of premature withdrawal from ongoing military coalitions. When coups or severe civil wars threaten incumbents' survival, leaders redirect finite military and political resources inward to bolster regime security, making sustained overseas deployments untenable. An analysis of coalition participation from 1950 to 2001 shows that states facing coups or intensified civil conflict are significantly more likely to defect from ongoing missions. The study contributes to the literature by centering leadership survival as a determinant of coalition reliability and by disaggregating coalition types to show how institutional design shapes the costs and feasibility of withdrawal. The findings carry important policy implications for anticipating defection risks and designing more resilient coalitions, especially outside consolidated democracies.