WASHINGTON - It was a day of dueling tax plans. Moments after President Obama rolled out a sweeping overhaul proposal for corporate taxes - wiping out many deductions while reducing the corporate tax rate - Republican primary contender Mitt Romney introduced tax reductions of his own. The differences between the two plans reflect the divergent approaches to taxes underlying their election campaigns. Obama has chosen not to pursue changes in income tax rates, and instead wants to eliminate many of the tax breaks, deductions, and special strategies that allow many American companies to dramatically discount their amount of taxes they pay. Romney is relying on a new set of tax cuts on individuals, as well as corporate tax cuts he previously proposed, to jump-start the economy. Relying on traditional GOP supply-side economics, the plan presented today by the former Massachusetts governor adds more definition to 59-point economic plan he unveiled last year. The Romney proposal calls for a 20 percent reduction in marginal tax rates - which are the taxes paid on the portion of income that places higher earners in the upper tax brackets. That is a change from the plan Romney released last year, in which he called for no change in marginal tax rates.