High Quality Content by WIKIPEDIA articles! The Mutual Defense Assistance Act was a United States Act of Congress signed by President Harry S. Truman on 6 October 1949. For US Foreign policy, it was the first U.S. military foreign aid legislation of the Cold War era, and initially to Europe. The Act followed Truman`s signing of the Economic Cooperation Act (the Marshall Plan), on April 3, 1948, which provided non-military, economic reconstruction and development aid to Europe. The Act was reauthorized in 1950, but in 1951, it and the Economic Cooperation Act were succeeded by the Mutual Security Act, and its newly created independent agency, the Mutual Security Administration, to supervise all foreign aid programs, including both military assistance programs and non-military, economic assistance programs that bolstered the defense capability of U.S. allies.