<P> For an overview on the different perspectives concerning optimal balance between public and private power in the economy, see liberal, realist & Marxist . For more detail on specific systems of thought relevant to debate on this fiscal policy see Keynesian economics, Monetarism, the Austrian School, New classical macroeconomics, Real business - cycle theory, and New Keynesian economics . A key common feature of the anti-Keynesian schools of thought is that they argued for policy ineffectiveness or policy irrelevance . Although the theoretical justifications vary, the various schools all hold that government intervention will be much less effective than Keynes had believed, with some advocates even claiming that in the long run interventionist policy will always be counterproductive . </P> <P> Keynesian economics followed on from the Keynesian Revolution . In contrast to the recent resurgence of Keynesian policy making, the revolution initially comprised a shift change in theory . There had been several experiments in policy making that can be seen as precursors for Keynes' ideas, most notably President Franklin D. Roosevelt's famous "New Deal" in the United States . These experiments had been influenced more by morals, geopolitics and political ideology than by new developments in economics, even though Keynes had found some support in the US for his ideas about counter-cyclical public works policy as early as 1931 . </P> <P> According to Gordon Fletcher, Keynes' General Theory provided a conceptual justification for New Deal - type policies which was lacking in the established economics of the day . This was immensely significant, as in the absence of a proper theoretical underpinning there was a danger that ad hoc policies of moderate intervention would be overtaken by extremist solutions, as had already happened in much of Europe . However, Keynes did not agree with all aspects of the New Deal; he considered that the almost immediate revival of business activity after the program's launch could only be accounted for by dangerous - to - rely - on psychological factors, such as the boost to confidence effected by Roosevelt's inspiring oratory . </P> <P> While working on his General Theory, Keynes wrote to George Bernard Shaw "I believe myself to be writing a book on economic theory which will largely revolutionize, not I suppose at once but in the course of the next ten years--the way the world thinks about economic problems...I don't merely hope what I say, in my own mind I'm quite sure". Keynes's ideas quickly became established as the new foundations for mainstream economics, and also as a leading inspiration for industrial nations economic policy makers from about 1941 to the midseventies, especially in the English speaking countries . The 1950s and 1960s period, when Keynes's influence was at its peak, to many appeared in retrospect to have been a golden age . </P>

Widespread acceptance of the keynesian theory of fiscal policy