So Arthur Laffer — still arguing the improbable “supply side” proposition that cutting income tax rates generally raises total tax revenue — is apparently now a special adviser to John McCain. And McCain has taken on a big consignment of the snake oil, to Greg Mankiw’s dismay. The political temptation for a Republican candidate to promise both lower tax rates and higher revenues is irresistible. The policy-makers who cut taxes when Ronald Reagan and George W. Bush, respectively, came to power subscribed to this claim. Remarkably, at the same time, the economists who were the chief economic advisers to Reagan and Bush during these tax cuts disavow the proposition that they increase revenue (Murray Weidenbaum, Martin Feldstein, Glenn Hubbard, Mankiw…) . Almost all serious economists – let us say Ph.D. economists – disagree with this proposition, with only a microscopic handful of exceptions like Laffer. Indeed some of the advisers who defend the Reagan and Bush economic policies claim that this formulation of supply side economics is a caricature, and was not the true rationale of the tax cuts. This wishful thinking is directly at odds with quotes from the presidents themselves and their Treasury secretaries and other economic officials, to the effect that tax cuts stimulate income so much as to produce more tax revenue. Laffer is not a straw man. (See my next post.)