Former Bush economist dumps on supply-siders

I thought this was interesting, coming as it does from a former chairman of President Bush's Council of Economic Advisers (Greg Mankiw, in case you don't feel like clicking though).

Mankiw quotes a John McCain interview with National Review in which the Senator declares:

Tax cuts, starting with Kennedy, as we all know, increase revenues.

Actually, of course, we don't know that at all. Sometimes marginal tax rates are so high that the Laffer curve applies: Cut the rates, and you bring in more revenue than you would have otherwise. But those rates have to be really high--probably much higher than the 35% top rate on income that now applies (or the 39.6% rate that applied before the Bush tax cut). And so Mankiw writes:

I doubt that, in fact, Senator McCain believes we are on the wrong side of the Laffer curve. But unfortunately, fealty to the most extreme supply-side views is de rigeur in some segments of the Republican party.

Including, one should note, the segment to which the President who hired Mankiw belongs.