Why did the Alliance break down in 1944 - 45?
There were many aspects to the Alliance breaking down between 1944 and 1945 these are the long term hostility between the USA and the USSR, the arguments at the Yalta and Potsdam conference and the different personalities in the big and the change of leadership within USA and Britain.
In 1917 civil war broke out in the USSR. The USA, Britain, France and the other countries decided to try and wipe out communism by force. They invaded the USSR in support of the White Russians, however although the White Russians were supported by the non communist countries the Bolsheviks managed to establish themselves. They renamed the country the Soviet Union and it became a Communist dictatorship which lasted till the early 1990's.
When it came to conferences like Yalta and Potsdam there was already hostility and tension between the big three because in previous years the USA and Britain had sent troops to try and destroy the very government they were trying to negotiate with.
The USA and the USSR had hugely different ideological differences which lead to further tension between the two nations. Stalin believed that all property was owned by the state on behalf of the people and that people were provided with the pay that they would need to live, on the other hand Roosevelt believed that land was owned by individual people and they were free to earn as much money as they wished. This meant that when Stalin and Roosevelt met at conferences like Yalta they had completely different principals about how their country should be run. This lead to further strain to their political relationship.
At Yalta the Big Three managed to make some agreements on the future of Europe and...