Hillary Clinton's tax policy on gas and oil is "pointless" while John McCain's is "evil," according to New York Times columnist Paul Krugman. But in explaining the difference, Krugman betrays either his ignorance of the flawed history of the so-called "windfall profits tax" on petroleum or his tacit approval of the tax despite its folly as public policy.

From Krugman's April 29 Conscience of a Liberal blog post (emphasis mine, paragraph breaks removed):

Anyway, John McCain has a really bad idea on gasoline, Hillary Clinton is emulating him (but with a twist that makes her plan pointless rather than evil), and Barack Obama, to his credit, says no. [...] The Clinton twist is that she proposes paying for the revenue loss with an excess profits tax on oil companies. In one pocket, out the other. So it’s pointless, not evil. But it is pointless, and disappointing.

Far from being pointless, a windfall profits tax produces negative effects on consumers and investors, as well as the health of the energy industry, say many economists, including former Bill Clinton economic advisor Robert J. Shapiro who focused his fire on the policy's damage to retirees' investments (see PDF of study here).

Washington Post reporters Alec MacGillis and Steven Mufson found another liberal economist with nothing positive to say for a windfall profits tax in their May 1 front-page article (emphasis mine):