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And with that new television ad and more, Mitt Romney is stepping up his campaign activity, and this is after months of keeping a low profile. He and the other Republican presidential candidates are debating yet again this evening. And while poll numbers for many of them have risen and fallen quickly, Romney's support has remained stuck at about 25 percent. NPR's national political correspondent Mara Liasson explores what that might mean going forward.
MARA LIASSON, BYLINE: One of the biggest surprises of this year's Republican primary campaign has been the lack of a serious challenge to Mitt Romney. Conservative activist Erick Erickson, who runs the RedState.com website, says while there have been tons of televised debates, there's been very little debate about Romney's record.
ERICK ERICKSON: A lot of the vetting that Republican voters would normally do he hasn't gone through. They've been so focused on the anti-Romney, who's going to be the alternative.
LIASSON: One candidate after another has auditioned to be the anti-Romney. They've shot to the top of the polls, then fizzled. But even the best funded of them all, Rick Perry, has chosen to run ads attacking President Obama, not Romney.
(SOUNDBITE OF AD)
PRESIDENT BARACK OBAMA: We've been a little bit lazy, I think, over the last couple of decades.
GOVERNOR RICK PERRY: You believe that? That's what our president thinks wrong with America? That Americans are lazy? That's pathetic.
LIASSON: While there have been a handful of anti-Romney ads from Republicans, an analyst for the Campaign Media Analysis Group says there's been no focused negative assault on Romney. And that's given Romney a free pass to focus on the man he considers his true rival: Barack Obama.
(SOUNDBITE OF AD)
MITT ROMNEY: I think the president fails to understand America. I don't think he understands what makes America work. And I, you know, I think he honestly believes that a government in Washington with well-intentioned bureaucrats can do a better job guiding the country than can free individuals and free enterprises.
LIASSON: Since there's no concerted Republican attack on Romney, the job has fallen to the Democrats.
STAN GREENBERG: It's very important, I think, for them to do it given how inept the Republican challengers are to raising the issue. You know, he's a flip-flopper and the character problem.
LIASSON: That's Democratic pollster Stan Greenberg. He can't think of another campaign when the incumbent president's party has gone after a potential opponent so early. Democrats are also trying to magnify a perceived disconnect between Romney and ordinary Americans. This ad was made by an independent Democratic super PAC called Priorities USA.
(SOUNDBITE OF AD)
UNIDENTIFIED MAN: And while Romney doesn't want millionaires like him to pay a nickel more, he doesn't see the big deal in letting taxes go up by $1,000 for hardworking Americans.
LIASSON: The Obama campaign considers Romney to be the likeliest nominee. Romney plays that up, tweaking the president's campaign for having an obsession with him. A relatively unimpeded path to the nomination should be every candidate's dream. No one wants to end the primary season beat up and broke. But sometimes a vigorous nominating battle is a good thing, not a bad thing, says GOP strategist Ed Rogers.
ED ROGERS: You want to have as much momentum, excitement and intensity as possible. Usually, you get there by having a tough contest that produces some drama and some defining moments, and then that person comes out of the primaries with a pretty sharp edge. But if you just sort of flop around and everybody else dies, it doesn't give you the push and the momentum that you would like to have.
LIASSON: That's more or less what happened to John McCain in 2008, while Barack Obama had a drawn-out fight to the finish with Hillary Clinton and emerged a stronger candidate for it. A relatively tame Republican primary also means Romney will never have to fight to convince conservatives he is one of them. And that worries Erick Erickson. He's no fan of Romney's, but he wants to beat President Obama, and he doesn't think conservatives will ever be enthusiastic about Romney.
ERICKSON: I don't think you will ever see passion for Mitt Romney. He will be the accepted nominee to beat Barack Obama, and that will be it.
LIASSON: Although many GOP leaders believe Romney's nomination is all but inevitable, Ed Rogers, a veteran of Republican primary politics, thinks it would be a mistake to make that judgment now.
ROGERS: Leading at 25 percent, you know, by definition suggests that your lead is very fragile, and people are still looking. I think more than half of what's going to drive votes next year lies in front of us, not behind us. Right now, mostly, it's a bunch of activists and media kind of chasing each other around where the true rank-and-file voters really haven't engaged.
LIASSON: But they will soon. The first votes are cast in Iowa on January 3rd. Mara Liasson, NPR News, Washington.