Why Risk an Alliance? Evidence from Japan (1901-1960)

All alliances pose some risk to their signatories – the risk of provoking the mutual adversary and the risk of being entrapped in a war between the ally and the mutual adversary. States try to secure alliance terms that minimize such risks. Given this preference, when, how, and why do states agree to risky alliance terms? I test levels of threat, ally dependency, and militarism as potential explanatory variables of variation in alliance risk by examining all six of Japan’s alliances with Western great powers. I find the strongest relationship between threat and alliance risk, and the weakest relationship between militarism and alliance risk.
Mina Erika Pollmann is a PhD candidate in Political Science at MIT. Her research interests focus on Japan’s security and diplomacy, US foreign policy in East Asia, and international relations in the Asia-Pacific. After graduating from Georgetown University’s School of Foreign Service with a BS in Foreign Service, she worked for TV Tokyo-America and a DC-based risk consulting start up. Mina is a recipient of the National Science Foundation Graduate Research Fellowship, and was a Visiting Research Fellow at the University of Tokyo Institute of Social Science (November 2020-July 2021).