Rand Paul on Possible Mitt Romney Run: 'No, No, No, No'

Ted Cruz also piled on.

Romney “would have made a great president,” added Paul, rumored to be considering his own White House bid. “But to win the presidency you have the reach out and appeal to new constituencies. And I just don't think it's possible.”

“And if he thinks, ‘Well, I'm just going to change a few themes and next time I'll reach out to more people,’ I think it's a little more visceral than that,” the libertarian lawmaker said of Romney.

“I think in 2012, the reason Republicans lost can be sum up it in two words: 47 percent,” Cruz said at the forum.

Just months before the 2012 election, Romney was caught on tape at a private fundraiser telling guests that they shouldn’t “worry about” the 47 percent of people “who are dependent upon government, who believe that they are victims, who believe the government has a responsibility to care for them, who believe that they are entitled to health care, to food, to housing, to you-name-it.”

“I don't just mean that comment,” Cruz said. “The central narrative of the last election, what the voters heard, was, ‘We don't have to worry about the 47 percent.’ And I think Republicans are and should be the party of the 47 percent.

“We should be fighting for the little guy who has dreams and hopes and desires,” he said.

“I think he put it all into the race,” Rubio said. “He's someone who's earned the right to decide whatever it is he wants to do.”