Why are transitions from authoritarian rule often marked by spikes in communal violence? Through examining Indonesia's recent transition to democracy, this book develops a novel theoretical explanation for this phenomenon that also accounts for why some communities are vulnerable to violence during such transitions while others are able to maintain order. Yuhki Tajima argues that repressive intervention by security forces in Indonesia during the authoritarian period rendered some communities dependent on the state to maintain intercommunal security, whereas communities with a more tenuous exposure to the state developed their own informal institutions to maintain security. As the coercive grip of the authoritarian regime loosened, communities that were more accustomed to state intervention were more vulnerable to spikes in communal violence until they developed informal institutions that were better adapted for less state intervention. To test the theory, Tajima employs extensive fieldwork in, and rigorous statistical evidence from, Indonesia as well as cross-national data. "In this book, Yuhki Tajima combines bold theorizing and painstaking analysis to draw profound lessons from the wave of violence that accompanied Indonesia’s democratic transition. Highlighting the interaction between state interventions and informal institutions, he makes a major contribution to our understanding of communal violence and order." Edward Aspinall, Australian National University "Yuhki Tajima joins the debate on collective violence in post-New Order Indonesia with a powerful deployment of village- and census-level data, careful theory construction, and process analysis of multiple local settings. This intelligent book promises to bring Indonesia to the center of broader scholarship on the origins of communal violence." Benjamin Smith, University of Florida "In The Institutional Origins of Communal Violence, Yuhki Tajima skillfully links the shifting politics of government security policies to the eruption of communal violence in democratizing Indonesia. This book provides an important and creative new perspective on the intertwining of state and non-state violence." Paul Staniland, University of Chicago 'Tajima argues that ‘mismatches between formal and informal institutions’ explain violent conflict in post-New Order Indonesia. …The book offers a useful contribution by drawing attention to the importance of non-state, local forms of policing and conflict prevention that have been effective at preventing violence in the absence of state enforcement.' Jacques Bertrand, Bulletin of Indonesian Economic Studies This book develops a novel theoretical explanation for why transitions from authoritarian rule are often marked by spikes in communal violence. Yuhki Tajima is Assistant Professor in the Edmund A. Walsh School of Foreign Service and a core faculty member of the Asian Studies Program at Georgetown University. He has written articles for the American Journal of Political Science, the Journal of East Asian Studies, and The World Bank Indonesian Social Development Papers. He has consulted extensively for The World Bank and the United Nations Development Programme and was a researcher at the Federal Reserve Board of Governors. His work has been supported by The World Bank, the Asian Development Bank, Innovations for Poverty Action, the Institute on Global Conflict and Cooperation, and the Pacific Rim Research Program.