The purpose of both the truman doctrine and
the marshall plan was to
(1) support the construction of the iron curtain
(2) increase membership in the united nations
(3) prevent the spread of communism
(4) attempt to solve world hunger

The purpose of both the Truman Doctrine and the Marshall Plan was to (3) prevent the spread of communism. The Truman Doctrine used the the containment policy, so that the United States could support any nation with both economic and military aid if needed if its ability was threatened by Communism or the Soviet Union. The Marshall Plan was an initiative from the United States to Europe, which was economic support to help rebuild European economies after World War II.