As World War II approached, Hoover fiercely but unavailingly opposed the pro-Allied policies of Roosevelt, arguing that the United States should follow a "Fortress America" strategy, enhancing its own defenses but remaining aloof from European conflicts. In 1940–1941 Hoover unavailingly sought to overcome British opposition to the provision of food to populations in Axis-occupied regions of Europe. He subsequently called for the establishment of a new organization for the peaceful settlement of international disputes.
Roosevelt denied Hoover any official governmental role, but Harry S. Truman, who became president in 1945, deliberately and shrewdly treated him as a respected elder statesman. Although staunchly, even sometimes obsessively, anticommunist, in April 1945 Hoover initially recommended that the president accept Soviet predominance in Eastern Europe. As international food supplies dwindled, in February 1946 Truman sent Hoover on a global mission to assess the situation and made him coordinator of food relief for thirty-eight countries. Albeit with some caveats, Hoover publicly endorsed the Marshall Plan. His congressional testimony and support were also crucial to establishing and funding the United Nations International Children's Emergency Fund (UNICEF).
Hoover's internationalism had its limits, however. The new North Atlantic Treaty Organization (NATO) left him uneasy, as he believed that Europe contributed too little to its own defense. Hoover supported continuing aid to Guomindang leader Jiang Jieshi after the 1949 communist victory in China and opposed U.S. recognition of the new regime. Hoover initially supported the June 1950 U.S. intervention in Korea but opposed Douglas MacArthur's subsequent decision to cross the 38th Parallel into North Korean territory.
The Truman administration's decision in late 1950 to enhance troop commitments in Europe provoked Hoover's December 1950 "Gibraltar America" address. He publicly urged the withdrawal of U.S. troops from continental Europe, leaving Europeans responsible for their own defense, and also called for limiting U.S. commitments to the island bastions of Britain, Japan, Taiwan, and the Philippines. He repeatedly advocated expelling the Soviet Union and its communist satellites from the United Nations (UN). His speech triggered what was termed the Great Debate between isolationists and internationalists on American foreign policy. His stance, much derided by influential contemporaries and rejected by the Republican Party when it nominated Dwight D. Eisenhower for president in 1952, won Hoover considerable posthumous respect from the 1960s' New Left. Interestingly, in 1954 he opposed potential U.S. intervention in Indochina. Hoover died in New York City on 9 July 1964. Priscilla Roberts
Herbert Hoover Reassessed: Essays Commemorating the Fiftieth Anniversary of the Inauguration of Our Thirty-First President. Washington, DC: U.S. Government Printing Office, 1981.; Burner, David. Herbert Hoover: A Public Life. New York: Knopf, 1978.; Doenecke, Justus D. Not to the Swift: The Old Isolationists in the Cold War Era. Lewisburg, PA: Bucknell University Press, 1979.; Wilson, Joan Hoff. Herbert Hoover: Forgotten Progressive. Boston: Little, Brown, 1975.