Keynes was an influential economist who advocated government intervention in the modern capitalist economy. His initial motivation for studying economics was to reduce rife mass unemployment due to the Great Depression. In effect, Keynes made a systematic instrument for the U.S. government to create a robust economy. Therefore, the government's prime responsibility and national goal is for a tax payer funded welfare state with federal investment and expenditure (like building infrastructure) which may be needed to assure continuing full employment because private enterprises cannot provide full employment without interventionism by the government. According to the reading of Keynes Hayek, his ideas were introduced into The Truman's administration (experimented by the implementation of Marshall Plan), the Eisenhower's administration (minimized recession by use of "automatic fiscal stabilizers"), the Nixon (design of "a full employment budget"), and Jimmy Carter (approval of the Humphery-Hawkins Full employment)