Barry Posen


Barry Ross Posen is Ford International Professor of Political Science at MIT and the director of MIT's Security Studies Program. An expert in the field of security studies, he currently serves on the editorial boards of the journals International Security and Security Studies and is a member of the Council on Foreign Relations and served as a study group member for the Hart-Rudman Commission. Posen is a structural realist.
Posen received his B.A. from Occidental College in 1974 and his M.A. and PhD, under Kenneth Waltz, from the University of California, Berkeley in 1976 and 1981 respectively. Posen worked as a consultant for the RAND Corporation and an analyst for the Department of Defense and Center for Strategic and International Studies before becoming an assistant professor of political science at Princeton University in 1984. In 1987, he joined MIT as associate professor of political science and has taught at MIT since that time. He has also served as a consultant to the Woodrow Wilson Center, The Christian Science Monitor and the MacArthur Foundation.
Posen is the author of three books. Posen has also published a number of highly influential journal articles, including "The Security Dilemma and Ethnic Conflict" and "Command of the Commons: The Military Foundations of U.S. Hegemony." In addition to his scholarly work, Posen has frequently appeared in the media and published general interest articles in publications including The New York Times, The Boston Globe, and The American Interest.
Barry Posen is not closely related to the American economist Adam Posen, although their last name has the same origin from the city of Poznań in Poland.

Publications

Inadvertent Escalation

Posen's second book is Inadvertent Escalation: Conventional War and Nuclear Risks, which was published by Cornell University Press in 1991.

Restraint

Posen's third book is Restraint: A New Foundation for U.S. Grand Strategy, which was published as part of the Cornell Studies in Security Affairs series in 2014. The book is about two competing American grand strategies: liberal hegemony and restraint. Restraint contains Posen's critique of liberal hegemony and his explanation for why restraint is a superior grand strategy.
Reviewer William Ruger, writing in The American Conservative, called the book the "defining treatise" for supporters of restraint.

Putin's Preventive War: The 2022 Invasion of Ukraine

In his 2025 article Prof. Posen basically agrees with Prof. John Mearsheimer and with radio host Scott Horton, that the Russian invasion of Ukraine was a preventive war aimed to forestall Ukraine's admission into NATO, which could have been followed by placing nuclear-tipped cruise missiles too close to the Russian heartland to be defended from. Posen, like other analysts, draws parallels between the Cuban Missile Crisis of 1962 and the Russian Invasion of Ukraine of 2022.

Selected publications

  • Posen, Barry R.. "European Military Autonomy: What Comes First?". Survival. 67 : 7–28...
  • Posen, Barry R.. "Putin's Preventive War: The 2022 Invasion of Ukraine". International Security. 49 : 7–49...
  • Posen B. Hypotheses on the implications of the Ukraine-Russia war. Defense Priorities; 2022.
  • Posen, Barry R.. "A new transatlantic division of labor could save billions every year!". Bulletin of the Atomic Scientists. 77 : 239–243.