During World War II, Great Britain, the US, and the Soviet Union were allies against the Axis Powers. This meant that they had the common goal of stopping Germany, Japan, and Italy from taking over Europe. In February of 1945, Stalin, Roosevelt, and Churchill met at the Yalta Conference to discuss the plan for Germany after the war. Stalin’s presence in Europe outnumbered that of the US and Great Britain, and the fight against Japan was not over yet. Because of this, Roosevelt did not want to push Stalin too hard from his path because the U.S. needed the help from the Soviet Union against its fight with Japan.
In July of 1945, President Truman met with Stalin and the new Prime Minister of Great Britain, Clement Atlee. During that meeting, a plan was made for Germany to be divided into four zones, each being occupied separately by the US, the Soviet Union, France, and Great Britain. Stalin wanted to keep all of the nations he had occupied during the war, making them communist nations as well, whereas the US wanted the Soviet Union control to be temporary. Stalin would not promise to allow free elections in those nations.
Once the war was over, the Allies split Germany into two parts: East Germany, led by communist Stalin, and West Germany, led by the noncommunist United States. Just as Stalin wanted, almost all of the nations in Eastern Europe became communist states under Soviet control.
The Soviet Union and the United States were now superpowers, but now that Germany had been defeated, the two nations had little in common. The US was a capitalist democracy and believed in free elections. The Soviet Union was a dictatorship, meaning that Stalin controlled all aspects of the nation, and those who defied or questioned him could be imprisoned or put to death.
Truman was worried that the spread of communism would not only affect Eastern Europe, but also that it would extend into other parts of the world. To counteract the spread of communism, Truman promised aid to nations struggling against communism. The Soviet Union naturally backed any nation wanting the opposite. Because both nations were so very different, it was only a matter of time before their friendship became shaky.