Tax group: Deduction cap only offsets some of Romney tax plan

Those findings are roughly in line with an analysis released by the Tax Policy Center, which found last week that a $25,000 deduction cap would raise $1.3 trillion over a decade.

The tax center, a joint venture of the Urban Institute and the Brookings Institution, has estimated that Romney’s tax proposals would lower revenues by about $4 trillion over a decade, meaning a $25,000 cap would make up about a third of the difference.

Romney’s corporate tax proposals would lower revenues by another $1 trillion, the center has found. The Tax Policy Center also reported that getting rid of all itemized deductions would raise around $2 trillion, or about half the cost of Romney’s tax plan. 

The GOP nominee’s campaign pushed back hard against the Tax Policy Center study last week, as it has against other studies that sparked questions about whether Romney’s tax math adds up. Romney has said that his tax reform plan will be revenue-neutral, with tax cuts being paid for by eliminating tax breaks.

Romney’s camp said that the Tax Policy Center analysis was “misleading and deceitful,” and that the former Massachusetts governor has said a deduction cap was only one possible option for tax reform. Romney has also floated the idea of a $17,000 cap and a $50,000 cap. 

The Tax Policy Center has stressed that it never claimed to be analyzing Romney’s tax plan, in part because the GOP nominee has not released a fully fleshed-out proposal.

Romney and his running mate, Rep. Paul RyanPaul Davis RyanGOP leaders pitch children's health funding in plan to avert shutdown Lawmakers see shutdown’s odds rising Fix what we’ve got and make Medicare right this year MORE (R-Wis.), have said they want to work with lawmakers to hammer out those details.

The details of Romney’s tax plan have become a central topic in the presidential campaign, with Romney continually trying to bat away charges from President Obama that his tax plan amounts to a $5 trillion tax cut.

In its newest report, Citizens for Tax Justice noted that it had previously found that taxpayers making north of $1 million would see their tax bill go down under Romney’s plan, even if they had to give up essentially all of their tax breaks.