To what extent did relations between the Superpowers change between 1945 and 1955?
In 1945 the relations between the USA and Russia, though not entirely friendly, were okay however, they had lost their common cause and enemy after World War 2 and Roosevelt, who had believed that negotiation and compromise were the way forwards, had died. They were very suspicious of each other and after the war, the old rivalries and suspicions reappeared. In 1955 the Superpowers were against each other in two rival alliance systems (NATO and the Warsaw Pact), and rivalry had increased dramatically.
In 1945, Stalin began to expand the Soviet Union and created an 'Iron Curtain' between the Soviet Union and Western Europe. The 'Iron Curtain' was given the name after Churchill used it in a speech to describe the barrier of countries surrounding Russia that had now turned to communism. Stalin wanted this because 26,000,000 Russians had died in the war, and so he wanted to make sure that Russia could never be invaded again.
It was also a good way of spreading communism and making Eastern Europe a secure communist trading zone for the Soviet Union. The USA wasn't happy about this because they were forcing communism upon countries, refusing them free elections and setting up Soviet-controlled communist governments. This made the relations between the Superpowers worse as the Soviet Union continued to expand which the USA didn't like and so this increased rivalry.
Truman was a strong anti-communist and was very angry that the Stalin was spreading communism, so he created the Truman Doctrine. The Truman Doctrine was a US policy of containment created in 1947. It was created as Truman believed that the Soviet Union was trying to spread communism, they wanted to use the atom bomb along with their superior...