The US and the Soviet Union were the two superpowers during the Cold War, each leading its own sphere of influence. The War was the continuing state of conflict, tension and competition that existed between the United States and the Soviet Union and their allies from the mid-1940s to the early 1990s. Throughout this period, rivalry between the two superpowers was expressed through military buildup, propaganda, espionage, weapons development, industrial advances, and competitive technological development such as the space race. Both superpowers engaged in costly defense spending, a massive conventional and nuclear arms race, and numerous wars in third world countries. Although the US and the Soviets had been allies during World War I, they both sharply disagreed after the conflict on many topics, particularly over the shape of the post world war. No actual physical fighting occurred between the Soviets and United States but it was considered a War because of the battle and struggle for world supremacy.
Each of these nations wanted to crush the other and shape the world to their own views.
The blame for the Cold War cannot be placed on one person. It can be argued that the Cold War was inevitable, and therefore no one's fault, due to the differences in the capitalist and communist ideologies. Since it was impossible for these ideologies to coexist together, the Cold War grew hot and the US and Soviets expressed their conflict towards each other in many different forms.
Many historians believe that mutual misperception played a major role in the cause of the Cold War. This means that both sides saw their ideology and actions were justified and would benefit the whole world. In the United States, the government is elected by free elections. The people can form political parties to voice their political opinions.