Supply-side economics: mythes et réalités

Est-ce que les supply-siders disaient que baisser les impôts d'un dollar augmenterait les revenus d'un dollar à cause de la croissance économique? Richard Rhan dans The Wall Street Journal:

Those of us who argued in the late 1970s and early 1980s for lower tax rates were often characterized as “radical supply-siders” and criticized for claiming that all tax-rate reductions lead to higher tax revenues. This was untrue; none of the principal advocates of Reagan’s 1981 tax cuts made this claim.

The Reagan tax cuts reduced rates for all income classes, even though it was well understood that cutting the lower rates would result in substantial revenue losses. Low tax rates (below 20%) do not cause much of a disincentive for working, saving or investing, and hence there is little supply-side effect. We did argue, however, that reducing the high marginal rates (up to 70% on high-income earners) would cause little, if any, revenue loss, because of the large, positive supply-side effects. (...) CBO figures show that total tax revenue only fell from 19.2% of gross domestic product (GDP) in 1982, before most of Reagan’s tax-rate reductions were put in place, to 18.4% of GDP in 1989, the year he left office. This happened because the U.S. economy grew by more than one-third in real terms (34.3%), much faster than the 24.3% rate expected even by economists within the Reagan administration.