Why did the relationship between the United States and USSR change from 1941 to 1955?

After World War II, relations between the U.S. and the U.S.S.R rapidly deteriorated. The United States believed it had behaved honorably to the Soviets, by, for example, holding back its troops from entering Berlin because it had agreed the Russians could take that city.

The relationship between the United States and the USSR had always been strained because the political ideologies each supported, capitalism and democracy in

the US and communism and a command economy in the USSR, were opposed to one another. Their relationship was further tested following Stalin’s decision to sign

the non-aggression pact, or the Nazi-Soviet Pact, with Nazi Germany in 1939. Stalin’s decision and occupation of Poland in 1939 led the United States to publicly

condemn the USSR. While angry with the USSR, the United States did not forget that Nazi Germany was the greatest threat to international collective security.

Explanation:

Hope this helps alot

necessary and proper clause. the congress shall have power to all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this constitution in the government of the united states, or in any department or officer thereof.