ABC News' Michael Falcone reports:

TAMPA, Fla. - Rep. Jason Chaffetz, a Utah congressman and prominent Mitt Romney backer, laced into Newt Gingrich on Tuesday night for a robo-call paid for by the Gingrich campaign alleging that Romney took kosher meals away from Holocaust survivors .

"There are a lot of rhetorical barbs in a campaign," he said, "but that went over the line."

"To say that it didn't go through the normal vetting process, that's not good enough," Chaffetz said. "An accident of that magnitude will not be forgotten."

Chaffetz, who spent several days in Florida attending Gingrich's campaign events to offer a counter-weight to the former House speaker, said he would be in Nevada on Friday and Saturday ahead of the state's caucuses and might play the same role there.

"In this day and age of instant communication, you want to be able to respond in real time," he said in an interview with ABC News at Romney's Florida primary night party in Tampa. "To be there on site and offer a real perspective - especially if something absurd or ridiculous is said - pays dividends."

He also said he did not buy into Gingrich's attempt to position himself as the anti-establishment, conservative alternative to Romney.

"I'm as Tea Party as they get, I'm as conservative as they get," he said. "I got 100 percent rating from the American Conservative Union, and I'm 100 percent Mitt Romney."

Gingrich, he added, "could not get elected Speaker right now, and he used to run the place."

Chaffetz predicted that it would be all but impossible for Gingrich - or any other candidate - to capture the nomination now, citing the former Massachusetts governor's message and superior resources.

He described the Romney campaign's war room in Tampa as a "NASA launch center."

"It's so impressive how organized they are," he said, "It's unbelievable."