Politifact has evaluated the claims in the spot and rated them "Mostly False," mainly because Romney's proposals are too vague to evaluate thoroughly. Romney has rejected the conclusions of the Tax Policy Center, cited in the ad, that he would be unable to cut taxes for the wealthy and the deficit as much as he has promised without also getting rid of much-beloved middle-class tax perks. "They made an assumption that I would reduce the home mortgage-interest deduction," he's told Fortune. "I will not do that for middle-income taxpayers."
From a political standpoint, what's going on here is clear: We are watching the inversion of the tradition anti-tax script by Democrats, who are now casting the Republican GOP presidential nominee as the man who will increase middle-class taxes.
"Mitt Romney, he's so focused on big business and tax cuts for the wealthy, it's seems like his answers to middle-class America are just tough, tough luck," says the female narrator of the spot.
And Republicans are playing into the trap with a mixture of vagueness and complaints about the 47 percent who do not pay federal income taxes -- an echo of the Tea Party-fostered demand that all Americans begin to pay federal income taxes, even if only $10 a year, as Michele Bachmann proposed earlier this year.
On CBS's 60 Minutes last weekend, Romney was pressed on the issue and gave up an opportunity to be clear with voters.
"What are we talking about, the mortgage deduction, the charitable deduction?" Scott Pelley asked.
"The devil's in the details. The angel is in the policy, which is creating more jobs," Romney replied.
"You have heard the criticism, I'm sure, that your campaign can be vague about some things. And I wonder if this isn't precisely one of those things?" Pelley pressed.
Instead of using the interview to say no, he would not eliminate the popular mortgage-interest deduction, Romney made a process point: "It's very much consistent with my experience as a governor which is, if you want to work together with people across the aisle, you lay out your principles and your policy, you work together with them, but you don't hand them a complete document and say, 'Here, take this or leave it.'"
Nor did he do himself much good when he told a presumably middle-class audience in Kent, Ohio, Wednesday, "By the way, don't be expecting a huge cut in taxes, because I'm also going to get rid of deductions and exemptions."
The Obama campaign, meanwhile, has stuck to its message.
Romney would "[r]aise taxes on the middle class by cutting deductions like those for mortgage interest, children, and charitable contributions to pay for $250,000 tax cuts for multi-millionaires," Obama campaign spokesman Danny Kanner reiterated in a statement earlier this week.
It will be interesting to see if this argument comes up -- and how it's handled -- during the first presidential debate next week.