What foreign policy was the most effective containment strategy?

The most effective containment strategy in U.S. foreign policy was the Truman Doctrine, which articulated a commitment to support countries resisting communist expansion. This policy was operationalized through various means, including military aid, economic assistance, and diplomatic efforts, exemplified by the Marshall Plan, which helped to rebuild Western Europe and prevent the spread of Soviet influence. By framing the struggle against communism as a global fight for democracy and freedom, the Truman Doctrine successfully galvanized international support and shaped U.S. foreign policy for decades.