sentences:  Prior to joining the George W. Bush Administration, Brooks was a vice president at the Center for Naval Analyses (CNA) and an advisor to Sandia National Laboratories.During the George H.W.Bush Administration, Brooks was Assistant Director for Strategic and Nuclear Affairs at the U.S. Arms Control and Disarmament Agency and was Head of the U.S. Delegation on Nuclear and Space Talks and Chief Strategic Arms Reductions (START) Negotiator in the State Department.