Walsh School of Foreign Service, the Center for Security Studies, and the Department of Government at Georgetown University. He is the author of ​Over the Horizon: Time, Uncertainty, and the Rise of Great Powers​ (Cornell University Press, 2017) and ​Occupational Hazards: Success and Failure in Military Occupations​ (Cornell University Press, 2008). He received his Ph.D. and M.A. from the University of Chicago and his B.A. from Colgate University.