Tobey is a senior fellow at Harvard University’s Belfer Center for Science and International Affairs. He was most recently deputy administrator for defense nuclear nonproliferation at the National Nuclear Security Administration. There, he managed the US government’s largest program to prevent nuclear proliferation and terrorism by detecting, securing, and disposing of dangerous nuclear material. Tobey also served on the National Security Council staff in three administrations, working in defense policy, arms control, and counterproliferation positions. He has participated in international negotiations ranging from the START I talks with the Soviet Union to the six-party talks on the denuclearization of the Korean peninsula.