The only way to lower tax rates without losing revenues will require, as it did for Reagan, broadening the tax base. That is, some things currently untaxed (or, as the case may be, permitted as tax deductions) will need to be taxed. This article includes a list of the top ten biggest such tax breaks. No surprise, of course, are such things as the mortgage-interest tax break.
Worth thinking long and hard about these tax breaks – who benefits from them and how they cost everyone else in the form of higher tax rates overall and, perhaps more importantly, in terms of economic distortions and incentives.