Tax Proposals by Republican Presidential Candidates Tax Policy Center The Tax Policy Center has compared in a detailed grid the provisions of the tax plans proposed by the eight major Republican presidential candidates. TPC will update the grid as candidates reveal more details about their tax plans.In addition, TPC has analyzed the distributional effects of tax proposals from Mitt Romney, Newt Gingrich, Herman Cain, and Rick Perry, and will conduct similar evaluations of proposals from other presidential candidates as they make sufficient detail available.