U.S. senator from Missouri (1953–76) who was a staunch advocate of a strong national defense but became an outspoken critic of U.S. military involvement in Vietnam, which he believed was irrelevant to U.S. security.

Symington served in World War I, attended Yale University (1919–23), and entered public life in 1945 as chairman of the Surplus Property Board in the administration of President Harry S. Truman. Symington later became assistant secretary of war, secretary of the air force, and chairman of the National Security Resources Board. In 1956 and 1960 he made unsuccessful bids to become the Democratic presidential candidate. As a senator, he was remembered for his commitment to national defense. He warned before the launch of Sputnik in 1957 that the U.S.S.R. was assuming a dominant position in science and military power. Symington was a vocal opponent of the Vietnam War, believing it to be unimportant to U.S. foreign interests and damaging to the nation's economy. Before his retirement in 1977, he decried excessive secrecy by the United States concerning nuclear weapons stored on foreign soil.