All Taxes Considered

Romney will consider all federal taxes, including income, payroll, estate and corporate taxes, economic adviser Glenn Hubbard said in an April 30 interview. Hubbard noted that economists differ on which income groups bear the burden of some of those taxes.

Because almost half of all households don't pay income taxes, Romney's proposed rate cuts won't benefit them and their other taxes would be largely unchanged. Instead, his plan would shift the burden within the upper-income half: those who get more tax benefits now would pay more taxes and those who get fewer would pay less.

Romney, who made $21.6 million in adjusted gross income in 2010, paid a 13.9 percent tax rate, according to tax returns he released, because most of his income came from investments. With a fortune estimated at as much as $250 million, he would benefit from eliminating the estate tax, now 35 percent with a $5.1 million exemption per person.

"He's the first president who would massively cut his own taxes," Sullivan said.

Obama's Proposal

In contrast, President Barack Obama has proposed that high- income taxpayers pay higher tax rates on wages, capital gains and dividends. He would limit their deductions and prevent tax increases for married couples making less than $250,000 a year and individuals making less than $200,000.

Under Obama's most recent budget, taxpayers in the top 1 percent would have an average tax increase of $93,707 in 2013, according to the nonpartisan Tax Policy Center in Washington. The middle 20 percent of taxpayers would receive an average tax cut of $40.

As evidence that Romney's plan is feasible, Hubbard pointed to a report by the co-chairmen of the 2010 bipartisan fiscal commission, Erskine Bowles and Alan Simpson, which also set a top 28 percent tax rate.

"You have a clear road map in Bowles-Simpson," Hubbard said.

Deficit Commission Plan

Unlike Romney's plan, the deficit commission's proposal called for eliminating corporate tax breaks alongside rate reduction and ending the break for investment income. It suggested limiting tax breaks for charitable contributions, mortgage interest, retirement savings and health insurance.