Final answer:
The blank in the question should be filled with 'Warsaw Pact', which was a military alliance formed in 1955 by the former Soviet Union and its satellite states in Eastern Europe.
Step-by-step explanation:
The blank in your question should be filled with 'Warsaw Pact'. The Warsaw Pact was a military alliance formed in 1955 by the former Soviet Union and its satellite countries in Eastern Europe. The Soviet Union created this pact as a counter to the North Atlantic Treaty Organization (NATO), which was primarily formed by Western countries including the United States and Canada. Notable members of the Warsaw pact included Albania, Bulgaria, Czechoslovakia, Hungary, Romania, East Germany, and Poland. This pact was seen as a vital defense by Soviets against the united Western Europe, particularly against a resurgent Germany.
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