Rusk became special assistant to Secretary of War Robert P. Patterson, but in 1947 new Secretary of State George C. Marshall invited Rusk to head the State Department's Office of Special Political Affairs. In spring 1949 Rusk became deputy undersecretary of state. Major policy initiatives during his tenure included the Marshall Plan, the establishment of a separate West German state, and the negotiation of the North Atlantic Treaty.
In March 1950 Rusk became assistant secretary of state for Far Eastern affairs, formulating policy on the People's Republic of China (PRC), the Republic of China (ROC, Taiwan), and the Koreas. When the Democratic People's Republic of Korea (DPRK, North Korea) invaded the Republic of Korea (ROK, South Korea) in June 1950, Rusk recommended firm action and military intervention under international United Nations (UN) auspices. A firm supporter of Chinese Nationalist leader Jiang Jieshi, whom Chinese communist forces drove from the mainland to Taiwan in 1949, Rusk strongly opposed U.S. recognition of the new PRC. His varied experiences reinforced his conviction that aggressive totalitarian powers of both Left and Right must be uncompromisingly opposed.
During 1951–1961 Rusk headed the Rockefeller Foundation, greatly expanding aid programs to the developing world. In 1961 President John F. Kennedy appointed Rusk secretary of state. Rusk placed special emphasis on improving relations with the Soviet Union, pushing arms control agreements, including the 1963 Partial Test Ban Treaty (PTBT) and the 1968 Non-Proliferation Treaty (NPT), and increasing aid to developing countries. Generally speaking, he counseled moderation during the ongoing Berlin Crisis and the Cuban Missile Crisis.
Initially skeptical of Kennedy's growing U.S. troop commitments in Vietnam, Rusk, under President Lyndon B. Johnson, who relied far more heavily on his advice, became increasingly dedicated to the proposition that the United States must resist communist aggression there. He reluctantly acquiesced in the 1963 coup against South Vietnamese President Ngo Dinh Diem, who had failed to institute domestic reforms that Rusk considered essential. Erroneously holding communist China primarily responsible for expanding North Vietnamese and Viet Cong military efforts, Rusk uneasily supported Johnson's escalation of the war in 1965. At that time Rusk opposed peace negotiations, fearing that his country would enter them from a position of weakness.
Although concerned that excessive American escalation might trigger outright war with China, Rusk supported subsequent troop increases and Johnson's bombings of the Democratic Republic of Vietnam (DRV, North Vietnam) and rarely favored bombing halts to facilitate potential peace talks. He became the war's most ardent official defender, clashing repeatedly with J. William Fulbright, chairman of the Senate Foreign Relations Committee. After the communist 1968 Tet Offensive, Rusk staunchly backed U.S. commander General William C. Westmoreland's request for 200,000 additional American troops. When Johnson rejected his advice in March 1968, Rusk's influence began to wane. He played only a minor role in the Paris peace talks that opened in May 1968.
His reputation tarnished by his exhausting years in office, a deeply scarred Rusk left the State Department in 1969, teaching international law at the University of Georgia until 1984 and eventually writing his memoirs. He died in Athens, Georgia, on 20 December 1994.
Papp, Daniel S., ed. As I Saw It: By Dean Rusk As Told to Richard Rusk. New York: Norton, 1990.; Schoenbaum, Thomas J. Waging Peace and War: Dean Rusk in the Truman, Kennedy, and Johnson Years. New York: Simon and Schuster, 1988.; Zeiler, Thomas W. Dean Rusk: Defending the American Mission Abroad. Wilmington, DE: Scholarly Resources, 2000.