When Democrats regained control of Congress in the 1948 elections, President Harry Truman outlined to the 81st Congress (1949–1951) the “Fair Deal,” an ambitious follow-up to New Deal programs of the 1930s. But Truman’s domestic agenda became a Cold War casualty after the Soviet Union successfully tested its atomic bomb, China came under communist control, and a Soviet spy ring was uncovered. Congress enacted internal security legislation. It also approved U.S. entry in the North Atlantic Treaty Organization (NATO), anchoring an alliance intended to protect Western Europe from Soviet aggression. In June 1950, North Korea invaded South Korea.