NATO: The formation
The blockade also encouraged the Western allies to form the North Atlantic Treaty Organization (NATO).
The alliance was dominated by the USA. American influence has been reflected in the fact that every single supreme command NATO has been an American. The formation of NATO was a milestone in American foreign policy. Never before had the USA been a member of a peacetime military alliance. The fact that Truman broke with all the traditions of American foreign policy shows how determined he was to stop the spread of communism.
NATO was more than a promise of American help in case of emergency. The alliance was to be supported with large numbers of troops on the ground. In particular there was a large build-up of NATO forces in West Germany. By 1953, five divisions of US troops were permanently based in Germany.
The Soviet Union felt threatened by this. The sense of threat increased in 1955 when West Germany joined NATO. The Soviet Union responded by setting up its own military alliance in 1955. This was established under a treaty called the Warsaw Pact. For the next three decades NATO and Warsaw Pact forces faced each other and prepared for war.