DENVER -- A comment by Republican presidential nominee Mitt Romney earlier this week regarding how he would overhaul the U.S. tax code set off a back-and-forth between the Romney and Obama campaigns on Wednesday.The Obama campaign seized on Romney's comments in an interview with a local TV station in Colorado Monday night, saying that his mention of a possible $17,000 cap on itemized deductions would mean higher taxes for "many families." The campaign used the example of a family of four making $125,000 a year, and another of a family of three with an annual income of $85,000.