High Quality Content by WIKIPEDIA articles! The Truman Doctrine is a set of principles of U.S. foreign policy created on March 12, 1947 by President Harry S Truman. In his speech to the Congress, Truman declared that the United States, as "leader of the free world", must support democracy worldwide and fight against communism. The approach was conceived with the help of George Marshall and Dean Acheson, two influential associates. The Truman Doctrine represented the harsh aspect of containment policy, and the Marshall Plan was the soft side. The declaration of the Truman Doctrine served to inhibit the formation of coalition governments that included communist elements.