1968, plus many others in support roles outside Vietnam. Johnson refused to allow the trained men of the Army reserves or the National Guard to serve in Vietnam, because that would involve Congressional oversight. Instead he relied increasingly on the draft, which became increasingly unpopular. With college deferments from the draft widely available, out of the 2.5 million Americans who served in Vietnam (out of 27 million Americans eligible to serve in the military) 80% came from poor and working-class backgrounds. In August 1964 Johnson secured almost unanimous support in Congress for the Gulf of Tonkin Resolution, which gave him very broad discretion to use military force as he saw fit. South Vietnam had a large Well-equipped army, but it left nearly all the fighting to the Americans. In February 1968 the Viet Cong launched an all-out attack on South Vietnamese forces across the country in the Tet Offensive. The ARVN (South Vietnam's army) successfully fought off the attacks and reduced the Viet Cong to a state of ineffectiveness; thereafter, it was the army of North Vietnam that was the main opponent. However the Tet Offensive proved a public relations disaster for Johnson, as the public increasingly realized the United States was deeply involved in a war that few people understood. Starting in 1964, the antiwar movement began. Some opposed the war on moral grounds, rooting for the peasant Vietnamese against the modernizing capitalistic Americans. Opposition was centered among the black activists of the civil rights movement, and college students at elite universities. Republicans, such as California Governor Ronald Reagan, demanded victory or withdrawal, while on the left strident demands for immediate withdrawal escalated. Nixon and Ford 1969–1977 President Richard Nixon (1969–74) radically transformed American policy, with the aid of his top advisor Henry Kissinger. First of all he rejected the long-standing containment policy that made it the highest goal to stop the expansion of communism. By playing off the two main communist rivals, China and the USSR, he managed to put a pause on the Cold War through friendly relationships with each of them, or Détente. Moscow and Beijing went along, and accepted Nixon's terms of pulling their support away from Vietnam. This allowed Nixon to turn that war over to the government of South Vietnam, withdrawing all American and Allied troops, while continuing a bombing threat. The Vietnamization policy seemed to work until 1975, when North Vietnam militarily