Abstract.：Does the partitioning of states along ethnic lines reduce conflict? While theorists drawing on the “security dilemma” argue that partition prevents conflict recurrence by separating the parties, others dispute these findings. Advancing in four analytical steps, this work first reconceptualize partition as decreased cohabitation in dyads between transnationally defined ethnic groups. Based on a global dataset (1945-2017), we find that whereas complete partition reduces internal conflict, its incomplete application increases this risk. The second step adopts a nationalist logic and tests whether partition reduces conflict if it eliminates dyadic domination. Third, the analysis focuses on whether reduced domination makes civil conflict less likely, with or without border change. We show that power sharing can be at least as effective in reducing domination as partition. The fourth and final step investigates the various side effects of state splits on both civil and interstate conflict. Generally, we find that partition may fuel instability both within and outside the dyad.

Lars-Erik Cederman is professor of international conflict research and leads the department of humanities, social and political sciences at ETH Zürich. He taught at the Graduate Institute of International Studies in Geneva, Oxford University, UCLA, and Harvard University. In 2019, he was elected as member of the German academy of sciences. He is the author of Emergent Actors in World Politics: How States and Nations Develop and Dissolve (Princeton University Press, 1997), and co-author of Inequality, Grievances and Civil War (with Kristian Gleditsch and Halvard Buhaug; Cambridge University Press, 2013), and Sharing Power, Securing Peace? Ethnic Inclusion and Civil War (with Simon Hug and Julian Wucherpfennig; Cambridge University Press 2022). He published in American Political Science Review, American Journal of Political Science, International Organization, World Politics, American Journal of Sociology, and Science. His research interests include nationalism, state formation and conflict processes.