During the Cold War, what was the main concern of the United States?

The Cold War (1947–1991) was a geopolitical struggle between the capitalist West, led by the U.S., and the communist East, led by the Soviet Union. After World War II, both superpowers possessed nuclear weapons capable of unprecedented destruction. American leaders worried that communist governments would take control of more countries—by force, revolution, or political influence—threatening democracy and free markets worldwide. The threat of nuclear war remained constant, particularly during crises like the Cuban Missile Crisis in 1962.