Welcome! I am an Assistant Professor in the Edmund A. Walsh School of Foreign Service at Georgetown University, where I am a core faculty member of the Security Studies Program.

I am a scholar of International Relations, specializing in questions related to American grand strategy. My first book, forthcoming with Cornell University Press, examines grand strategy and its outcomes in the context of military alliances. It argues that leading great powers often fail to promote their desired military capabilities among smaller allies because their grand strategic demands clash with the risks presented to the allies by hostile great powers that are scrutinizing the alliance’s actions. My second book, co-authored with John Mearsheimer and forthcoming with Yale University Press, undertakes a theoretically grounded investigation on the question of whether the United States—which has been the sole “regional hegemon” in the international system since the late 19th century—should fear the rise of another regional hegemon in Europe or East Asia.

My other works delve into a wider range of issues that arise in debates surrounding grand strategy, including preventive war, the relationship between power politics and international norms, the performative use of violence, and the making of political order. I am especially keen on developing theoretical insights using declassified primary documents and historiography on U.S. foreign policy during the Cold War, as well as the American Civil War and Reconstruction. Some of my research has been published or is forthcoming in outlets such as the American Political Science Review, International Studies Quarterly, European Journal of International Security, Texas National Security Review, Contemporary Security Policy, and Political Science Quarterly.

Policy analysis and commentary based on these works can be found in forums like The Diplomat, Foreign Affairs, Foreign Policy, and the Washington Quarterly, as well as podcasts hosted by the Cato Institute and War on the Rocks.

My research has been supported by the Smith Richardson Foundation, the Charles Koch Foundation, and the Korea Foundation for Advanced Studies, as well as the Center for East Asian Studies and the Pearson Institute for the Study and Resolution of Global Conflicts at the University of Chicago, among others.

Before beginning my academic career, I served as the personal interpreter to South Korea’s Chairman of the Joint Chiefs of Staff. In this capacity, I assisted the Chairman during all interactions with English-speaking foreign partners, including the Commander of the U.S. Forces Korea (CDRUSFK), Commander of the U.S. Pacific Command (CDRUSPACOM), and the Chairman of the U.S. Joint Chiefs of Staff (CJCS).

I received a Ph.D. in Political Science from the University of Chicago in 2022. I also hold an M.A. in Political Science from the University of Chicago and a B.A. in International Studies and Political Science, summa cum laude, from Korea University. Before joining the faculty at Georgetown, I was an Assistant Professor of Political Science at Boston College. I have also held the Stanton Nuclear Security Junior Faculty Fellowship at the Massachusetts Institute of Technology’s Center for Nuclear Security Policy, the Global Innovation Program Postdoctoral Fellowship at the University of Pennsylvania’s Perry World House, and the Hans J. Morgenthau Predoctoral Fellowship at the Notre Dame International Security Center.

Contact: joshua.byun<at>georgetown<dot>edu.