Clinton spoke on Wednesday night at the Democratic convention in Charlotte, delivering a 48-minute address that was roughly 10 minutes longer than than the president's Thursday night speech. Asked if Clinton could be elected president today, Romney responded: "You know, if the constitution weren't in his way, perhaps. But I don't know the answer to that."
The day after Clinton's speech, Romney released a TV ad that sought to play Clinton against Obama. The ad pointed to comments Clinton made during the 2008 Democratic presidential primary campaign, in which he cast doubt on Obama's claim that he consistently opposed the war in Iraq.
Clinton will campaign for Obama in Florida and Ohio next week.
"Meet The Press" host David Gregory spoke with Romney over of two days this week, and also interviewed Ann Romney. It's the first time since 2009 that Mitt Romney has sat for an interview with the Sunday news program.
In the interview, Romney also said he wants to "maintain defense spending at the current level of the GDP" and that Republican leaders and the president were wrong to agree to defense spending cuts that were part of last year's deal to raise the debt limit.
"I thought it was a mistake on the part of the White House to propose it. I think it was a mistake for Republicans to go along with it," Romney said.