At the end of World War II, there was a war between two groups of nations. The Soviet Union and the Axis powers. The Soviet Union was mainly consisted of the United States,Britain,France,and Russia,which was made up of democratic republic system. Then the Axis power consisted Germany,Italy,and Japan,which was based on dictatorship. In June 1941,the Axis powers invaded the Soviet Union. The United States started to view that the Soviet Union was being overrun by the Axis powers,and was further reinforced in the aftermath of the Japanese attack on Pearl Harbor. Under the Lend-Lease Act, the United States consigned enormous quantities of war materiel to the Soviet Union, which was critical in helping the Soviets withstand the Nazi invasion.