Director, Belfer Center for Science and International Affairs; Belfer Professor of Technology and Global Affairs, Harvard Kennedy School; U.S. Secretary of Defense (2015-2017)
Fisher Family Fellow, Belfer Center for Science and International Affairs, Harvard Kennedy School; Deputy Secretary, U.S. Department of Energy (2014-2017); Special Assistant to the President and Senior Director for European Affairs, National Security Council (2009-2013); Deputy Assistant Secretary of Defense for Russia, Ukraine, and Eurasia (1994-1996)
