Newt Gingrich calls Mitt Romney “a liar”

By Bobby Caina Calvan, Globe Staff

Newt Gingrich called Mitt Romney “a liar” today for saying he has no role or responsibility for a barrage of negative ads that are credited with damaging the former House speaker’s campaign in Iowa.

During an interview with CBS News, Gingrich, who was the frontrunner in Iowa just two weeks ago, said it was “baloney” that Romney had nothing to do with the ads from an independent group, a super PAC called Restore our Future, which is backing the former Massachusetts governor. Those ads are credited, in part, with exposing Gingrich’s personal and congressional vulnerabilities. As Romney has risen to the top of the most recent polls in Iowa, where caucusgoers vote tonight, Gingrich has tumbled to the middle of the pack.

“This is a man whose staff created the PAC and his millionaire friends fund the PAC,” he said on “The Early Show.”

“He’s not telling the American people the truth,” Gingrich said. “It’s just like his pretense that he’s a conservative.”

When asked if he was calling Romney a liar, Gingrich answered “yes.”

Gingrich had vowed to run positive campaign and his advertisements have mostly focus on his ability to lead the nation. Today, however, he hinted today that he was reconsidering that tactic as the campaign shifts to New Hampshire and South Carolina.

The label of “liar” is particularly incendiary and goes beyond previous questioning of Romney as a malleable candidate, one prone to shifting positions on key issues.

Romney, responding to Gingrich’s charge that he’s not a conservative, told Fox News: ‘‘Perhaps people forget that I ran for president four years ago, you may recall that along with Mike Huckabee I was the conservative alternative to John McCain.’’

He has previously said he understood Gingrich’s anger over the ads but being a front-runner means being able to take the slings and arrows of the campaign.

Bobby Caina Calvan can be reached at bobby.calvan@globe.com. Follow him on twitter @GlobeCalvan.