It was the first major war of a larger conflict, the Cold War. The Cold War was a political, economic and military contest between the two post-war superpowers, the United States of America and the Union of Soviet Socialist Republics (Soviet Union). The Republic of Korea (south) was supported by the United States which persuaded the United Nations to side with her. Australia was one of the 21 members of the United Nations which sent military forces to aid the south. The Democratic People's Republic of Korea (north), was backed by China and the Soviet Union.