Cold War, a term used for the period of tense relations between the United States and the Soviet Union, stretching from the late 1940s to the late 1980s when Communism collapsed in Eastern Europe and the USSR ceased to exist. The two superpowers faced each other as leaders of conflicting political, economic and ideological alliances; became engaged in a nuclear arms race; and fought surrogate wars with each other in various locations in the Third World, from Korean, to Cuba and to Afghanistan. The two superpowers became rivals through immensely different social ideologies; different aims and ambitions; mutual distrust or fear and bad diplomatic relations from history. .
Based solely on the fact that the USSR and the United States had different forms of governments many tensions arose. The Western democracies sought a form of security for international free market; free trade; opportunity and economic competitions. .
Another main reason was that there was a long history of mistrust between the two countries.
The Cold War was characterized by mutual distrust, suspicion and misunderstanding by both the United States and Soviet Union, and their allies. At times, these conditions increased the likelihood of the third world war. The United States accused the USSR of seeking to expand Communism throughout the world. The Soviets, meanwhile, charged the United States with practicing imperialism and with attempting to stop revolutionary activity in other countries. Each block's vision of the world contributed to East-West tension. The United States wanted a world of independent nations based on democratic principles. The Soviet Union, however, tried control areas it considered vital to its national interest, including much of Eastern Europe.
With the threat of the Soviet Union no longer existing the U.S. is now free to use unlimited force against almost anyone it may choose. The end of the Cold War has caused its problems too as new enemies have needed to be invented.