After Germany surrendered, the allied Unites States and Soviet Union had different plans. It boiled down to control. The Soviet Union wanted control of many Eastern European countries. America saw the opportunity of trade vanish as Communism set into these countries. The distrust between the two countries was growing back.
The United States of America and the Soviet Union are bout powerful countries, and both have a strong distrust for each other. Neither side could accept the others actions as anything but devious and deceitful, as we see in the exchange below. This is what set the stage for the Cold war.
Before Japan was bombed, America refused to share scientific nuclear weapon information with its strained ally, the Soviet Union. President Truman did tell Stalin about “a extremely powerful weapon”. He left out that it was a nuclear bomb, and its calculated destructive power. Both leaders were keeping secrets however. Stalin non-chalantly stated that he hoped it would be used on the Japan soon. He did not tell Truman he knew about hat type of weapon they were speaking of, nor did he mention that the Soviet Union had its own “nuke” in the works. When the two leaders took leave of one another, Stalin ordered to speed up the development of a Soviet Nuclear bomb.
After the US “Nuked” Japan, the US had the ability to mold Japans future to suit American needs. The biggest fear the US had was communism. Thanks to the Soviet Union, communism was spreading in Europe, and The United States did not want Japan to become a Communist country as well, so America introduced political democracy. America also established independent trade unions.