If only it were an April Fools’ Day prank. With Japan officially cutting its corporate tax rate as of today, America now has the highest rate among advanced economies. Even its effective tax rate is way above average despite the likes of General Electric spending billions to game the labyrinthine code. A smarter approach would be to substitute a business consumption tax.

Now the United States might cling to second place if Japan cancels the rate reduction to help pay for the tsunami and earthquake devastation. After factoring in state taxes, America’s top rate of 40 percent would still exceed the average of 26 percent for the rest of the OECD.

Headline rates, of course, are like sticker prices on new cars. The real numbers are lower, thanks in part to the $40 billion companies spend annually to comply with, and often sidestep, the maximum levy. GE, for example, has taken heat for consistently paying less than what the U.S. tax code would imply it should.

But even taking into account the efforts of attorneys and lobbyists, the average effective U.S. rate in 2010 was 29 percent against 21 percent for international counterparts, according to the  American Enterprise Institute. And before the recession, corporate tax revenue as a share of U.S. GDP was at its highest since the 1970s.

Politicians of all stripes have been talking about lowering corporate taxes and eliminating loopholes to pay for a sharp rate reduction.  A sharply lower rate —  Canada’s will be just 15 percent in January 2012 — would boost worker wages, investment, productivity, jobs and growth. Such reforms, though a big improvement, would still leave in place a flawed and unwieldy structure.

A better alternative might be a consumption tax where business would simply determine its liability by subtracting total purchases from total sales. The tax would then be imposed on what’s left, essentially a firm’s value added. Unlike the corporate income tax, a consumption tax would allow the cost of investments to be fully deducted immedi ately, providing incentives for more. Such a tax also could be imposed on imports and deducted from exports, as other nations currently do with their VATs.

The Tax Policy Center estimates an 8.5 percent consumption tax — by broadening the tax base and boosting output – would boost corporate tax collections as a percentage of GDP to 4.5 percent from the 2.4 percent the White House forecasts for the next few years. (This is the corporate tax plan, by the way, found in Rep. Paul Ryan’s “Roadmap for America’s Future.”) That’s no laughing matter.