Final answer:
The Soviet Union viewed the Marshall Plan as a strategic initiative by the United States to solidify capitalist influence and reduce communist expansion, prompting them to reject and oppose the aid. NATO was seen as a direct military threat to Soviet security and interests in Europe, which led to the creation of the Warsaw Pact in response.
Step-by-step explanation:
The leaders of the Soviet Union viewed the formation of the Marshall Plan and NATO with suspicion and concern. The Marshall Plan, proposed by U.S. Secretary of State George C. Marshall, was a recovery plan that provided significant economic aid to help rebuild European nations after World War II, provided they spent it on American goods. This was seen as a strategic move to support capitalist economies and strengthen the United States' economic and cultural presence in Europe, counteracting the spread of communism. The Soviet Union, seeing this as an extension of American influence and an encroachment on their sphere of control, refused the aid and pressured its satellite nations to do the same. The formation of NATO, a defensive military alliance, further alarmed the Soviet Union since it was a direct military challenge to its influence in Europe, signaling the end of American isolationism and a commitment to collective security against potential Soviet aggression.
Meanwhile, Stalin's actions, such as the rigged elections in Hungary and the invasion of Czechoslovakia, helped make the case for the Marshall Plan in the eyes of its skeptics and highlighted the Soviet Union's desire to cement its control over Eastern Europe. These events convinced many in the West of the need to take proactive steps against the spread of communism. In response to NATO, the Soviet Union later established the Warsaw Pact, a similar military alliance for Communist nations, which served as a counterpart to NATO and solidified the division of Europe into competing blocs.