The tension between the democratic and the communist countries, called the Cold War, dominated American political and cultural life between 1945 and 1991. World War II (1939–45) left only two major superpowers standing: the United States and the Soviet Union. Although they had been allies in World War II, the countries had very different political systems. Each sought to dominate the postwar world. This struggle divided the world into two major groups: democratic nations led by the United States and communist nations led by the Soviet Union. Rather than existing peacefully, with each side content with its system of government, both the United States and the Soviet Union felt threatened by each other. The United States desired as many free trading partners as possible to keep the U.S. capitalist system going. The Soviet Union believed in the communist system, in which the state controls the economy and production...