What was the foreign policy called containment in history?

Containment was a U.S. foreign policy strategy adopted during the Cold War aimed at preventing the spread of communism beyond its existing borders. Formulated in the late 1940s, it was based on the belief that the Soviet Union and its influence could be contained through diplomatic, military, and economic measures. Key initiatives under this policy included the Truman Doctrine, the Marshall Plan, and military interventions in Korea and Vietnam. Ultimately, containment shaped American foreign relations and military strategies for several decades.