Secretary of Defense Robert S. McNamara testifies on behalf of the limited nuclear test ban treaty at a hearing before the Senate Foreign Relations Committee in Washington on August 13, 1963. He told the group the United States has nuclear warheads âäin the tens of thousandsâä and that the treaty would preserve a nuclear lead over Russia. Seated beside the Secretary is Harold Brown, director of defense research and engineering. (AP Photo/Charles Gorry)