Moving from the family farm to a clothing store in Kansas City, Harry Truman saw the store fail in 1921. He entered politics, became a Jackson County commissioner and judge in 1926. Truman was elected to the U.S. Senate in 1934 and narrowly won re-election in 1940. Chairman of a special Senate committee investigating inefficiently and corruption in the World War II military spending programs, he gained fame and the Democratic nomination for vice president in 1944.

Only 82 days into the vice presidency, Franklin D. Roosevelt died and Truman was president. Truman was faced with the final stages of World War II and the growing Russian interest in controlling Eastern Europe and at least part of Germany. It was during this period that the Cold War began. Truman's policy was one of containment. He helped form the North Atlantic Treaty Organization. During his first term, he alienated labor unions and businesses by attempting to prevent major strikes and maintaining price controls.

His victory over Thomas Dewey in 1948 was an upset. During his second term he faced the fall of China to the communists and the beginning of the Korean War.