Most analysts doubt that the convoluted tax system could be revamped by a deeply divided Congress in an election year, but the announcement is certain to fuel debate in the run-up to November's elections.

The plan, over a year in the making, is President Barack Obama's first official foray into reform of the tax code, which most experts believe badly needs a revamp after years of being loaded up with special provisions.

The centerpiece is a cut in the top corporate rate - now at 35 percent, among the highest in the industrialized world. That will appeal to businesses, which gripe that the current U.S. rate puts them at a competitive disadvantage.