Final answer:
Containment was a Cold War foreign policy strategy used by the United States to prevent the spread of Communism by limiting Soviet influence to its existing territories.
Step-by-step explanation:
Containment was the primary foreign policy strategy of the United States during the Cold War, aimed at preventing the spread of Communism beyond its existing borders. The strategy was first articulated by George F. Kennan in his Long Telegram, advising that Soviet influence should be contained through strong resistance and primarily through economic policy.
Containment policy influenced U.S. military and diplomatic actions for over thirty years, including the development of new policies like brinkmanship under President Eisenhower, which posited that readiness for war could be used to maintain peace.