The USA and the USSR were allies during WW2, but as soon as the war was over their friendship began to collapse. In the years 1943-49 relations grew worse and a cold war developed.
First of all the most important reason as to why relations grew worse was because the USA and the USSR did not trust each other. one reason for this was because of the extreme differences in political systems and the USA had always been suspicious of communism. Therefore this made relations worse because after they finished needing each in WW2 if they did not trust each other they would be unlikely to help the other nation if it did not benefit their own nation.
Therefore as soon war ended tensions began to rise. This can be seen at the Potsdam conference in july 1945, which is 5 months after the end of the war. I know tensions began to rise and the nations started to have disagreement when there were several disagreements at this conference.The second conference was the Potsdam conference in July 1945. In this conference things were different, Truman was now in charge and he saw things differently and didn’t trust Stalin as far as he could throw him! There were a number of disagreements for example the size of the reparations and the fact Truman did not tell Stalin that he had an Atomic Bomb. This fact worried Stalin and it even started a very long arms race.
As a result of Stalin’s fear the USSR tried to form a buffer zone of communists states on their western borders in the years between 1945 and 1948. For example they approached Czechoslovakia, Poland, Hungary, Bulgaria, Yugoslavia, Romania & East Germany! The plan was to try and make them all communist therefore increasing Stalin’s empire! This made relations worse because the USA then feared the spread of communism so they intervened and decide they needed to take action before it was too late and the communist spread was too large.
The USA was alarmed by Stalin’s takeover of Eastern Europe and decided to implement a policy of containment. They did this by implementing the Truman Doctrine and the Marshall plan. Truman thought it was his responsibility to stop the spread of communism; he called it the Truman Doctrine. For example, Greece was one of the countries that hadn’t turned to communism yet, in order to stop the communist rebels over throwing the government, Britain send its army to fight the rebels and protect Greece. But in 1947 when Britain told America they could no longer afford keeping their army there America sent its troops. This is just one example, next Truman offered aid to any country that hadn’t turned to communism that needed aid, a.k.a the Marshall Plan. This included America sending $17 billion dollars in