The warsaw pact:

Since the end of the war, Russia had set up pro-Russian communist governments in eastern and central Europe. By 1948 the Cominform had been formed and Russia had concluded mutual assistance treatieswith Poland, Bulgaria, Czechoslovakia, Hungary and Rumania. The confrontation over Berlin (1948-49) and the formation of NATO meant that the Cold War would continue. Soon after the Communist victoryin Indo-China, the anticommunist nations in Asia formed the South-East Asia Treaty Organization. In Europe, West Germany was admitted to the NATO in 1955 and allowed to re-arm. (West Germany wasessential to an overall defence system in Europe. As her economy advanced rapidly after 1950, her rearmament was of great help to the defence of western Europe. Because of Britain's promise not to withdrawher NATO forces from Europe (in order to counterbalance the German forces), France did not object to the admittance of West Germany into the NATO and West Germany's rearmament in the 9 PowerConference of 1954.)
Nominally the Warsaw Pact was a response to a similar treaty made by the Western Allies in 1949 (the North Atlantic Treaty Organization, or NATO) as well as the re-militarization of WestGermany in 1954, both of which posed a potential threat to the Eastern countries. Although it was stressed by all that the Warsaw Treaty was based on total equality of each nation and mutualnon-interference in one another's internal affairs, the Pact quickly became a powerful political tool for the Soviet Union to hold sway over its allies and harness the powers of their combined military. WhenHungary tried to extricate themselves from the agreement in 1956, Soviet forces moved to crush the uprising; and, in 1968, Soviet troops invaded Czechoslovakia (with support from five other Pactmembers), after the Czech government began to exhibit 'Imperialistic' tendencies.

Following the diminishing power of the USSR in the 1980s and the eventual fall of Communism the treaty became...