Describe two reasons for the changing relationship between the United States and the USSR changed from 1939 until 1961 Explain how these changes led to the Cold War

Explanation:

One reason relations worsened was because of the Soviet invasion of Czechoslovakia in 1968. Warsaw Pact forces crushed Dubcek's attempt at liberalizing his country, known as the 'Prague Spring', and this provoked expressions of outrage from the Americans. The relationship between the USA and the USSR deteriorated after World War II. Stalin's takeover of Eastern Europe was opposed by the US. The differing ideologies of communism and capitalism, dictatorship and democracy, separated the two countries when they emerged as competing superpowers. Tensions between the two nations at the end of World War II, the ideological conflict between both the United States and the Soviet Union, the emergence of nuclear weapons, and the fear of communism in the United States.