Why did the United States and Great Britain acquiesce to Soviet domination of so much territory at the end of WWII?

The post war order in Europe was agreed upon by the big 3 at Yalta. The Polish question was actually one of the biggest sticking points of the agreement. The English wanted the Polish government-in-exile based out of London to be the post war government while the Soviets wanted the Lublin Committee (communist puppets) to be the government after the war. Roosevelt was pretty ambivalent about the whole thing. He wanted a democratically elected government in Poland obviously, but he wasn't willing to sacrifice good relations with Stalin over it. By the end of Yalta Churchill had wrung a promise out of Stalin to permit a democratically elected government to form in Poland and all nations in Europe.

 

However, as the war came to a close Stalin ran roughshod over the agreement reached at Yalta. Communist led governments were quickly set up in Romania, Hungary, and Poland by the Soviets. In fact, the Soviets helped instigate the Warsaw Uprising broadcasting appeals for the Poles to attack the Germans. Once the uprising started the Red Army, which was sitting directly outside of Warsaw, did nothing to help. The Germans exterminated the Polish Home Army which surely would have resisted the Soviets creating a puppet state out of Poland.

 

Churchill resisted all of this but did not find much support from America. Just Roosevelt started siding with Churchill against Stalin he died. Truman, new to The Presidency, did not want to alienate Stalin. The fact of the matter is the Western Allies could not do much about the governments set up in Eastern Europe. They could never reach it before the Soviets did and attempting to penalize the Russians by ending lend-lease was idiotic. Stalin would have almost assuredly withdrawn from the war leaving the Western Allies to finish up Nazi Germany on their own.

 

The only places where America and Britain actually had a shot at stopping the Communist advance were Czechoslovakia and Germany. In the closing days of World War II, after America and Britain had crossed the Rhine and Russia had crossed the Oder, the generals of the Wehrmacht started disobeying orders en-mass. Their biggest priority was saving as many Germans as possible from the Communists in the east. In fact, General Wenck, who was in charge of the German 12th army holding the Elbe River against the West, turned his soldiers around -against orders- and marched east to fight the Soviets. This and other moves by rogue generals meant the American armies had clear routes east to Berlin and Prague. Bradley and other US generals were requesting permission to continue advancing past the line agreed upon at Yalta. It was Eisenhower who nixed this. He chose to let Berlin and Prague fall to the Russians.

/r/AskHistorians Thread