Mitt Romney is starting to spell out specifics for his tax reform plan in advance of his first debate with President Obama, describing what amounts to a choose-your-own-deduction approach.
The Republican presidential nominee got into detail briefly during an interview with Fox Denver affiliate KDVR -- and in doing so moved to undercut the Obama campaign narrative that he's hiding details of how he would cut taxes by 20 percent while still keeping his plan deficit-neutral.
Romney says deductions would have to be trimmed in order to make up the difference, and said that taxpayers could perhaps choose on an individual basis which ones to claim and which ones to lose.
He said they could fill up a $17,000 "bucket" with the deductions they want.
"As an option you could say everybody's going to get up to a $17,000 deduction; and you could use your charitable deduction, your home mortgage deduction, or others -- your health care deduction, and you can fill that bucket, if you will, that $17,000 bucket that way," Romney said.
He added: "Higher income people might have a lower number."
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A Romney campaign aide later said that the $17,000 cap could change, adding that Romney was only citing a number he had likely heard as part of congressional discussions. The aide also said the tax rate cut could be offset by putting a dollar cap on personal exemptions and reducing health care tax preferences.
Though the campaign has not said how much the 20 percent rate cut could cost, a separate source who worked with the deficit-reduction 'supercommittee' on Capitol Hill said it could cost up to $1.7 trillion over 10 years. The Romney campaign aide said that's "possible."
And Romney spokesman Kevin Madden said the ideas for offsetting the tax rate cut reflect only suggestions that might be considered as part of talks with Congress.
Though the candidate didn't definitively embrace these particular options, he may have opened the door to a wider conversation Wednesday night when he faces Obama in the first presidential debate.
The Obama campaign has hammered Romney for keeping to himself the particulars of how he'd cut taxes across the board while finding enough deductions to trim to keep the plan deficit-neutral.
"Romney has never explained how he would pay for his massive new tax cut for the wealthiest," Obama deputy campaign manager Stephanie Cutter said in a memo released Wednesday morning. "Romney won't name which deductions he'll eliminate, asking voters to trust that he'll work it out with Congress after the election."
Romney may at least come armed with his "bucket"-list proposal on stage in Denver Wednesday night.
Each campaign, though, has been carefully managing expectations for the showdown. Obama's advisers claim Romney arrives with practice from the primary season under his belt. Romney's advisers note Obama is the only one on stage tonight with any general election debate experience.
But Romney's campaign has gotten aggressive in the hours leading up to the faceoff. Republicans seized on a comment by Vice President Biden in North Carolina Tuesday in which he said the middle class has been "buried" over the last four years.
Romney and running mate Paul Ryan pointed to the admission as proof of what they've been arguing all along. The comment played into their central claim ahead of a debate on domestic policy that Obama's policies have hurt the middle class.
"We agree," Ryan said in Iowa. "That means we need to stop digging by electing Mitt Romney the next president of the United States."
The Obama campaign, though, called it a "desperate and out-of-context attack."
The debate, one of three this month in addition to a vice presidential forum, is both high-risk and high-reward. A well-phrased retort from either candidate could redound to their benefit in the polls, while an awkward moment could have the opposite effect.
Romney arguably has the most to gain. Though competitive with Obama in national polls, he's been slipping in key battlegrounds. The debate is a chance for him to close that gap, and potentially benefit simply from being on the same stage as the president.
Cutter tried to preempt several possible arguments by Romney with her lengthy memo Wednesday morning.
"For the next four years, President Obama has laid out real and achievable goals, and a specific path to get there, restoring middle-class security and creating jobs and long-term economic growth," she wrote. "Mitt Romney comes to this debate in a different position. He doesn't have any specific plans to move us forward -- only tired repeats that will take us back. ... So, Romney can use tonight's debate to fill in those details and finally, for the first time, explain his proposals or readjust his positions. Or he can spend 90 minutes doing what he does best: attacking the president, distorting his own record, and avoiding any and all details on his plans for this country."
The debate is a rare moment when millions of Americans fix their attention on one political event. Fifty-two million people tuned in to the first debate four years ago, and 80 percent of the nation's adults reported watching at least a bit of the 2008 debates between Obama and Republican John McCain.
Just 7 percent of likely voters have yet to pick a candidate, according to an Associated Press-GfK poll last month.
Romney's campaign fell further behind in the wake of a secretly recorded video released last month showing him telling campaign donors that 47 percent of Americans pay no federal income tax and believe they are victims who are entitled to government assistance. As a candidate, he said, "my job is not to worry" about them.
While Romney may draw attention to Biden's "buried" comment on Wednesday, it's likely Romney will face questions about the hidden-video remarks.
Wednesday's 9 p.m. EDT debate on domestic issues is sure to offer a blend of choreography and spontaneity. Both men have spent hours rehearsing with proxy opponents, yet know to expect the unexpected.
Half of the six, 15-minute debate segments have been allotted to topics related to the economy. The last three segments will focus on health care, the role of government and governing.
Romney and Obama debate again Oct. 16 and Oct. 22. The lone debate for the vice presidential candidates is Oct. 11.
Fox News' Kelly Chernenkoff, Fox Business' Rich Edson and The Associated Press contributed to this report.