The U.S feared that the affects on Post WWII countries were reinforcing the appeal of Communist parties. "On June 5, 1947, in an address at Harvard University, Secretary of State George C. Marshall advanced the idea of a European self-help program to be financed by the United States. On the basis of a unified plan for western European economic reconstruction presented by a committee representing 16 countries, the U.S. Congress authorized the establishment of the European Recovery Program, which was signed into law by President Harry S. Truman on April 3, 1948. Aid was originally offered to almost all the European countries, including those under military occupation by the Soviet Union. The Soviets early on withdrew from participation in the plan, however, and were soon followed by the other eastern European nations under their influence. This left the following countries to participate in the plan: Austria, Belgium, Denmark, France, Greece, Iceland, Ireland, Italy, Luxembourg, the Netherlands, Norway, Portugal, Sweden, Switzerland, Turkey, the United Kingdom, and western Germany" -The Editors of Encyclopedia Britannica