Vietnamization was a policy of the Richard Nixon administration to end U.S. involvement in the Vietnam War through a program to "expand, equip, and train South Vietnamese forces and assign to them an ever-increasing combat role, at the same time steadily reducing the number of U.S. combat troops". Brought on by the Viet Cong's Tet Offensive, the policy referred to U.S. combat troops specifically in the ground combat role, but did not reject combat by the U.S. Air Force, as well as the support to South Vietnam, consistent with the policies of U.S. foreign military assistance organizations. U.S. citizens' mistrust of their government that had begun after the offensive worsened with the release of news about U.S. soldiers massacring civilians at My Lai (1968), the invasion of Cambodia (1970), and the leaking of the Pentagon Papers (1971).

The Vietnam War was a conflict in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. It was the second of the Indochina Wars and was a major conflict of the Cold War. While the war was officially fought between North Vietnam and South Vietnam, the north was supported by the Soviet Union, China, and other communist states, while the south was supported by the United States and other anti-communist allies, making the war a proxy war between the United States and the Soviet Union. It lasted almost 20 years, with direct U.S. military involvement ending in 1973. The conflict also spilled over into neighboring states, exacerbating the Laotian Civil War and the Cambodian Civil War, which ended with all three countries officially becoming communist states by 1976.