Truman was born in Missouri and spent most of his youth on his family's farm. During World War I, he served in combat in France as an artillery officer in his National Guard unit. After the war, he briefly owned a haberdashery and joined the Democratic Party political machine of Tom Pendergast in Kansas City, Missouri. Truman was first elected to public office as a county official and became a U.S. Senator in 1935. He gained national prominence as head of the wartime Truman Committee, which exposed waste, fraud, and corruption in wartime contracts.
While Germany surrendered a few weeks after Truman assumed the Presidency, the war with Japan was expected to last another year or more. Truman approved the use of atomic weapons against Japan, intending to force Japan's surrender and spare American lives in a planned invasion; the decision remains controversial. His presidency was a turning point in foreign affairs, as his government supported an internationalist foreign policy in conjunction with European allies. Working closely with Congress, Truman assisted in the founding of the United Nations, issued the Truman Doctrine to contain communism, and passed the $13 billion Marshall Plan to rebuild Europe, including the Axis Powers of both world wars, whereas the wartime allied Soviet Union became the peacetime enemy, and the Cold War began. He oversaw the Berlin Airlift of 1948 and the creation of NATO in 1949. When communist North Korea invaded South Korea in 1950, he immediately sent in U.S. troops and gained UN approval for the Korean War. After initial success, the UN forces were thrown back by Chinese intervention and the conflict was stalemated through the final years of Truman's presidency.
On domestic issues, bills endorsed by Truman often faced opposition from a conservative Congress dominated by the South, but his administration successfully guided the American economy through post-war economic challenges. He said civil rights was a moral priority and in 1948 submitted the first comprehensive legislation, issuing Executive Orders the same year to start racial integration in the military and federal agencies. Corruption in Truman's administration, which was linked to certain members in the cabinet and senior White House staff, was a central issue in the 1952 presidential campaign which Adlai Stevenson, Truman's successor as Democratic nominee, lost to Republican Dwight D. Eisenhower. Popular and scholarly assessments of his presidency were initially negative, but eventually became more positive after his retirement from politics. Truman's 1948 election upset to win a full term as president is routinely invoked by underdog candidates.