Containment policy was a strategic approach employed by the United States during the Cold War to prevent the spread of communism beyond its existing borders. The policy aimed to contain Soviet influence through a mix of military, economic, and diplomatic strategies, reflecting a belief that communism posed a significant threat to democracy and capitalism. This approach influenced various U.S. actions and foreign policies throughout the Cold War era, shaping responses to events like the Yalta Conference and later conflicts such as the Vietnam War.