When the war ended Bundy, who married the daughter of future Secretary of State Dean Acheson in 1943, completed law school. Bundy practiced law for three years before joining the new Central Intelligence Agency (CIA) in 1950. Between 1953 and 1955 he successfully weathered charges by Senator Joseph McCarthy that he had contributed to the defense fund of Carnegie Corporation official Alger W. Hiss, accused of spying for the Soviet Union during the 1930s.
In 1956 Bundy became deputy assistant director of intelligence, a position he held until 1960. In 1956 he recommended that the United States assist the anticommunist government of President Ngo Dinh Diem of the Republic of Vientam (RVN, South Vietnam), a decision that tied successive American administrations to supporting the RVN against the Democratic Republic of Vietnam (DRV, North Vietnam).
Appointed deputy assistant secretary of defense in 1961, that fall Bundy recommended that President John F. Kennedy deploy U.S. troops to South Vietnam. After three months as assistant secretary of defense for international security affairs, in February 1964 Bundy became President Lyndon B. Johnson's assistant secretary of state for Far Eastern affairs and an influential policymaker on Vietnam. By 1964 Bundy privately doubted the value and wisdom of further long-term U.S. commitments to the RVN but publicly favored a strong line. In August 1964 he helped to draft the congressional Tonkin Gulf Resolution, granting Johnson virtually unlimited authority to use force in Vietnam. Bundy nonetheless urged—somewhat unavailingly—that besides fighting in order to demonstrate its resolve to win, the United States should concurrently seek to open negotiations to facilitate the withdrawal of U.S. military forces, a position enshrined in the November 1964 report of the Vietnam Working Group, which he chaired.
From the commitment of U.S. ground forces in spring 1965 onward, Bundy had serious reservations over the Johnson administration's continuing escalation of military commitments in Vietnam, but loyalty inhibited him from publicizing these or resigning, and he remained in office until the president left office in January 1969. As protests over the war intensified, Bundy and his brother McGeorge, national security advisor under Kennedy and Johnson, became increasingly controversial figures. Both featured prominently in journalist David Halberstam's highly critical 1972 account of why the United States had become so deeply involved in Vietnam, a responsibility that Halberstam and others ascribed to the influence of an elitist and activist U.S. foreign policy establishment to which, they alleged, Bundy and many of his colleagues belonged.
For the rest of Bundy's life, his role in Vietnam continued to dog him, provoking protests from influential Council on Foreign Relations members in 1971 when he was named editor of the organization's journal, Foreign Affairs. He held that post until he retired in 1984. Perennially wrestling with and seeking to elucidate the past, Bundy wrote but never published a lengthy memoir of his part in Vietnam policymaking. A lifelong Democrat, in 1998 he also produced The Tangled Web, a lengthy, somewhat critical study of President Richard Nixon's foreign policies. Bundy died of heart failure in Princeton, New Jersey, on 6 October 2000.
Halberstam, David. The Best and the Brightest. New York: Random House, 1972.; Kaiser, David E. American Tragedy: Kennedy, Johnson, and the Origins of the Vietnam War. Cambridge: Belknap Press of Harvard University Press, 2000.; Logevall, Fredrik. Choosing War: The Lost Chance for Peace and the Escalation of the War in Vietnam. Berkeley: University of California Press, 1999.