Nope, they did not have Poland nor the Balkans until after WWII. In fact, the spheres of influence were set up by FDR, Churchill, and Stalin, at Tehran and Yalta.
Learn about and revise the origins of the Cold War between 1914 and 1948 with this BBC Bitesize GCSE History (AQA) study guide.
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Basically, if you read history, Churchill was aghast that FDR would suggest that the British surrender their Empire on one hand, then allow Stalin to create another.
And yes, you are correct, the USSR was already there, but I am talking about the MASSIVE USSR that FDR allowed Stalin to get control of in negotiations, and almost immediately after the war, went back on his word about Poland, etc.............and Truman allowed that to happen. In essence, like it or not, all that happened is we exchanged one dictatorial regime controlling much of Europe, for another.