The Yalta Conference, in February 1945, was fairly successful. Churchill, Roosevelt, and Stalin agreed on a number of things:
They would join the United Nations Organization.
Stalin would join the war against Japan.
Germany, and Berlin, would be divided into four zones (American, British, French, and Soviet).
They would hunt down war criminals.
Eastern Europe would be seen as 'a Soviet sphere of influence.'
All countries liberated from Germany would be allowed to hold free elections.
The Big Three had to compromise about Poland. Stalin wanted to take Polish territory and allow Poland to take German territory. The other two let him have his way with Poland, but he had to agree to not interfere in Greece, where a civil war between monarchists and Communists was brewing.
The Communist parties have been raised to power far beyond their numbers and are seeking everywhere to obtain totalitarian control. This is certainly not the liberated Europe we fought to build. Nor is it one which allows permanent peace.
By the Potsdam conference the war-time alliance between the USA and the USSR had broken down. There were a number of reasons for this:
Stalin's armies occupied eastern Europe.
America had a new president, Truman, who was more anti-Communist than Roosevelt.
America had successfully tested an atomic bomb on July 16th 1945 one day before the conference had began but the USSR were aware of this due to embedded spies.
Very little was agreed at Potsdam. The three leaders at that time had many disagreements:
They disagreed over what to do about Germany.
They disagreed over Soviet policy in eastern Europe. Truman was unhappy of Russian intentions.
Stalin wanted to cripple Germany, Truman did not want to repeat the mistakes of Versailles.
They disagreed over reparations. Once again Stalin wanted to cripple Germany, and Truman wanted to avoid another war.
Truman was angry because Stalin had arrested non-communist leaders in Poland.
Truman dropped the atomic bomb so that Japan would surrender before Russian troops could go into Japan. America had the bomb in July 1945, but Truman did not tell Stalin about it. There was little surprise from Stalin however as records now show that Stalin was aware of the atomic bomb whilst it was being created by America due to his extensive spy network.
