Which president initiated the policy of containing communism during the Cold War?

Harry S. Truman initiated the policy of containing communism during the early years of the Cold War, which was a key element of U.S. foreign policy from the late 1940s onward. This approach aimed to prevent the expansion of Soviet influence and the spread of communism worldwide. Truman's doctrine, articulated in response to Soviet aggression, set the stage for American involvement in conflicts such as the Korean War and shaped the United States' strategic alliances with countries that were vulnerable to communist expansion.

Truman's containment policy included various measures, including military aid to Europe through the Marshall Plan and defining U.S. support for nations resisting communism, exemplified by the Truman Doctrine. This doctrine proclaimed that the U.S. would support countries threatened by communist takeover, making it a cornerstone of the Cold War strategy.

In contrast, while later presidents like Eisenhower, Kennedy, and Johnson played significant roles in Cold War policies, they built upon the foundational principles set by Truman. Eisenhower further developed the containment strategy through the concept of "domino theory," Kennedy escalated U.S. involvement in Vietnam alongside existing containment measures, and Johnson continued the trend but none initiated the containment policy itself. Thus, Truman is credited with officially starting the containment strategy that