The Survival and Breakdown of Victorious War Coalitions

States often take on coalition partners to secure victory in war, but afterwards their members may fall into conflict over the terms of the peace just secured, often at tremendous cost. What distinguishes those victorious coalitions that manage to sustain cooperation from those that disintegrate into hostility? To answer this question, I gather data on the characteristics of victorious wartime coalitions from 1859 to the present and estimate the duration of cooperation between their members in an event history framework. I explore the effects of coalition size, the diversity of preferences within the coalition, wartime alliance commitments, military strength, and several features of the war itself on the sustainability of peace amongst the members of victorious coalitions. While large coalitions are uniquely likely to break down, so are those with (a) diverse preferences and, surprisingly, (b) those comprised of a larger proportion of allies.