Author(s) Enze Han and Cameron Thies Keywords East Asia, state building, bellicist theories, civil conflicts, external threats, interstate rivalry, internal challenges Abstract This paper empirically tests bellicist theories of state building in the East Asian context, paying attention to the interplay between external threats and internal challenges and their implications for these states’ extractive power. How much variation in state building in the region can be attributed to war and war preparation as a result of both external threats and internal challenges? In particular, it provides more fine-grained analysis on the different types of internal challenges and their impact on state capacity building. The article argues that in the East Asia region, both external threats and internal challenges are crucial to explaining the variation in state capacity across the region. However, we also find that different types of internal challenges have different effects. Particularly, communist insurgencies seem to have both an immediate and long-term positive effect in compelling the state to respond with more extraction to engage in state-building efforts. DOI https://doi.org/10.1017/jea.2019.24 Author(s) Bio Enze Han is associate professor at the Department of Politics and Public Administration, The University of Hong Kong. He has published in journals such as World Development, Journal of Ethnic and Migration Studies, Journal of Contemporary China, The China Quarterly, The Pacific Review, Security Studies, Chinese Journal of International Politics, Cambridge Review of International Affairs, Conflict Management and Peace Science, among others. His books have been published with Oxford University Press and Routledge. Cameron G. Thies is professor and director of the School of Politics and Global Studies at Arizona State University. He has published in journals such as American Journal of Political Science, Journal of Politics, British Journal of Political Science, World Politics, International Studies Quarterly, European Journal of International Relations, and Comparative Political Studies, among others. His books have been published with Oxford University Press, Michigan University Press, Stanford University Press, and Routledge.