Acheson helped design the Truman Doctrine and the Marshall Plan, as well as the North Atlantic Treaty Organization.

[2] After 1949, Acheson came under political attack from Republicans led by Senator Joseph McCarthy over Truman's policy toward the People's Republic of China.

During the Cuban Missile Crisis of 1962, President John F. Kennedy called upon Acheson for advice, bringing him into the executive committee (ExComm), a strategic advisory group.

Acheson's well-known, reputed arrogance—he disdained the curriculum at Yale because it focused on memorizing subjects already known—was apparent early.

Because of his opposition to FDR's plan to deflate the dollar by controlling gold prices (thus creating inflation), he was forced to resign in November 1933.

[8] Brought back as assistant secretary of state on February 1, 1941, Acheson implemented much of Roosevelt's economic policy of aiding Great Britain and harming the Axis Powers.

In 1946, as chairman of a special committee to prepare a plan for the international control of atomic energy, he wrote the Acheson–Lilienthal report.

The Soviet Union's attempts at regional hegemony in Eastern Europe and in Turkey and Iran changed Acheson's thinking.

Acheson devised the policy and wrote Truman's 1947 request to Congress for aid to Greece and Turkey, a speech which stressed the dangers of totalitarianism (but did not name the Soviet Union) and marked the fundamental change in American foreign policy that became known as the Truman Doctrine.

[15] Published during the height of Mao Zedong's takeover, the 1,054-page document argued that American intervention in China was doomed to failure.

Although Acheson and Truman had hoped that the study would dispel rumors and conjecture, the documents helped to convince many critics that the administration had indeed failed to check the spread of communism in China.

When Soviet archives opened in the 1980s, however, research found that the speech had little if any impact on Communist decision for war in Korea.

Casey of Australia; and Lester B. Pearson of Canada, who famously observed in 1951 that "the days of easy and automatic relations with the United States are over'.

Both he and Secretary of Defense George Marshall came under attack from men such as Joseph McCarthy; Acheson became a byword to some Americans, who tried to equate containment with appeasement.

[26][27] He retired on January 20, 1953, the last day of the Truman administration, and served on the Yale board of trustees along with Senator Robert A. Taft, one of his sharpest critics.

During the Cuban Missile Crisis, for example, he was dispatched by Kennedy to France to brief French President Charles de Gaulle and gain his support for the United States blockade.

[29] During the 1960s, he was a leading member of a bipartisan group of establishment elders known as the Wise Men, who initially supported the Vietnam War.

[32] At 6:00 p.m. on October 12, 1971, Acheson died of a massive stroke, at his farm home in Sandy Spring, Maryland, at the age of 78.