NATO vs. Warsaw Pact The North Atlantic Treaty Organization (NATO) was established in 1949 by representatives from 12 nations (later 16 nations) : Belgium, Canada, Denmark, France, Iceland, Italy, Luxembourg, the Netherlands, Norway, Portugal, the United Kingdom, and the United States. Greece and Turkey joined in 1952, the Federal Republic of Germany in 1955, and Spain in 1982. The North Atlantic Treaty, which was signed in Washington, D.C., on 4 Apr 1949, provided for mutual defense and collective security, primarily against the threat of aggression by the Soviet Union. It was the first peacetime alliance joined by the United States. The Warsaw Treaty Organization (WTO), often called the Warsaw Pact, was a military alliance (1955-91) between the USSR and its Eastern European satellites. The WTO was established in Warsaw on 14 May 1955, as an Eastern counterpart to the North Atlantic Treaty Organization (NATO). The original Warsaw Pact nations were the USSR, Albania, Bulgaria, Czechoslovakia, the German Democratic Republic (East Germany), Hungary, Poland, and Romania. The WTO had a unified high command with headquarters in Moscow. Key posts in satellite forces were held by Soviet-trained or Soviet-born officers. In 1956, Hungary withdrew from the WTO but was pulled back into the alliance when Soviet troops crushed the Hungarian Revolution. In 1968, Czechoslovakia also attempted to withdraw but was forced back in by an invasion of Warsaw Pact forces led by the Soviet Union. Albania was allowed to resign in 1958. With the end of the cold war and the fall of the Communist regimes in Eastern Europe, the WTO lost its reason for existence.