Obama Campaign Ad Speculates Mitt Romney Might Have Paid Nothing In Taxes

A new ad released by the Obama campaign Thursday suggests that Mitt Romney might have paid nothing in taxes at some point. The ad plays a clip of a recent interview in which Romney said he was "happy to go back and look" to see if he had paid a rate lower than 13.9 percent -- but he never did get back to the voters on that.

"Did Romney pay 10 percent in taxes? 5 percent? Zero?" asks a narrator. "We don’t know."

The campaign says the ad is "following" Romney through Virginia, North Carolina, Florida and Ohio next week.

Senate Majority Leader Harry Reid (D-Nev.) recently ignited a firestorm of criticism by saying, in an interview with The Huffington Post, that a Bain investor had told him that Romney paid no taxes for 10 years. The presumptive GOP nominee has refused to release his tax returns for the years before 2010 despite bipartisan calls for him to do so.