Claire McCaskill wants Congress to pass a windfall profits tax on oil companies.

What would be the effects?

Well, first of all, gas prices would be higher, not lower. Demand for gasoline is inelastic, at least in the short run. Gas station owners are already squeezing out a mere two cents in profit per gallon of gasoline sold. Therefore, with no real retail markup, the higher wholesale gasoline costs incurred by distributors would have to fall on consumers at the pump in order for the retailers to break even. So we’re worse off here. If you like paying $4.00 per gallon, how about if we add another 20 cents or so to that?

And which investors will pay for the tax — the rich or the broad middle class? Robert Shapiro, President Clinton’s former undersecretary of commerce, argues that ownership of industry shares is "broadly middle-class," with the majority represented by institutional investments in mutual funds, pension funds, and individual retirement accounts that are held on behalf of millions of ordinary Americans. This coincides with my previous post about energy investors and who benefits from oil profits.

And, lastly, the early 1980s experiment with a windfall profits tax suggests that tax revenues would be significantly lower than expected. When Congress passed the windfall profit tax in 1980, the Congressional Budget Office projected that it would raise $393 billion in tax revenues. According to Congressional Research Services, it only raised $80 billion. That would be enough revenue to run the government for about 10 days, based on the 2008 fiscal budget.

Remember, gas prices are about three times as high in Germany and other European countries, where combined excise taxes, fuel taxes, windfall profits taxes, and VAT taxes are passed on by oil companies to the consumers. Oh, and if you factor in the exchange rate, they’re about 4.5 times higher.

So why are we debating this, again?