ABC

Conservative radio host and Fox News contributor Laura Ingraham said that Republican front-runner Mitt Romney may have a difficult time challenging President Obama in the general election, if Obama wows crowds in 2012 the same way he did last night at the Alfalfa Club Dinner.

Obama spoke at the 99th annual Alfalfa Club dinner Saturday evening, a closed dinner that is a who's who of the Washington elite.

"A bunch of us sitting next to each other, very prominent conservatives, former Bush cabinet members, we're looking at each other going, I don't know if Mitt Romney can beat him," Ingraham said today on the "This Week" roundtable.

"He's got to bring his 'A' game," Ingraham said of Romney. "It can't just be, you know, the kind of thing he's doing with [Newt] Gingrich, because Obama's operation is really smart, and I think they're going to run a tough campaign."

Ingraham said that Gingrich is starting to show signs of weakness in his effort to become a serious challenger to Romney's campaign.

"There's a rule of thumb in politics," Ingraham said. "If you're at a point where you're complaining about the other guy being mean and unfair and uncivil, that's probably a sign that you're losing.  And that's what he's facing right now."

Romney continues to widen his lead just days before the Florida primary, with two polls this weekend showing a double-digit lead for the former Massachusetts governor over the former House speaker.

"Time is not Newt Gingrich's friend, because the more time he has, the more he talks. And the more he talks, the more he says things," ABC's George Will said. "And we're at the horrid stage with Newt Gingrich."

But where time is not Gingrich's friend, taxes are trouble for Romney in a general election, ABC's Donna Brazile said.

"There's no question that Mitt Romney, in his record, his record at Bain Capital, his taxes, the fact that he has to now amend his financial disclosure form, Mitt Romney would be a great candidate to run against in terms of the economy," Brazile said.

Former Obama economic adviser Austan Goolsbee, now an ABC News consultant, said Romney's tax returns will be a problem for him in a general election against Obama.

"There's never been an actual candidate who personified the pathologies of the tax code that the president's been running against for the last several years," Goolsbee said, referring to Obama's proposed plan to raise taxes on wealthy individuals, like Warren Buffett and Romney, who pay a lower tax rate than the middle class.