SIOUX CITY, Iowa - Former House Speaker Newt Gingrich found himself on the defensive for his consulting contract with troubled lender Freddie Mac and his ideological consistency Thursday during the final televised debate before the Iowa caucuses.

Rep. Michele Bachmann accused Gingrich of "influence-peddling" for his $1.2 million contract with the government-related mortgage company as part of his post-Congress career, and hypocrisy for joining other conservatives in blaming Freddie Mac for helping cause the housing meltdown at the same time.

Gingrich said Bachmann was tossing "wild accusations" and "doesn't have her facts straight." He said he never lobbied for Freddie Mac and "was a private citizen engaged in business, like any other business."

"You don't have to meet the technical definition of lobbyist to be influence-peddling in Washington," Bachmann retorted.

In what may have been the last major chance to frame a case for the voters who will launch the party's nominating process in this state Jan. 3, the seven major Republican candidates jousted in a two-hour debate broadcast on Fox News. The action centered on rivals seeking to chip away at the credibility of Gingrich, the latest front-runner in the race, from several directions.

Asked directly how he responds to criticism from some conservatives that his mercurial nature and controversial career make him unelectable in the fall, Gingrich said he would crush President Obama in debate, and reminded viewers that Ronald Reagan was viewed initially as unelectable in 1980, too.

"Barack Obama will not have a leg to stand on in trying to defend a record that is terrible and an ideology that is radical," Gingrich said.

Texas Rep. Ron Paul, who has what Iowa hands believe is the strongest organization in the state and has been moving up in polls, said he was electable in the fall, despite his isolationist foreign-policy views: "The challenge isn't all that great in how we're going to beat Obama. He's beating himself."

Risking a late stumble

As much as it was an opportunity to help one's cause, the 13th debate of 2011 was also a minefield, presenting the risk of a major stumble with a dwindling number of days in which to recover from it.

Most of the contenders will be in Iowa for many of the next 19 days, with the exception of a brief Christmas truce, accompanied by the inescapable din of television and radio attack ads.

In recent weeks, Gingrich shot into the lead, the latest in the rotation of candidates elevated by conservative voters seeking an alternative to Mitt Romney, but there were signs before the debate began that the former speaker's support was beginning to soften. Did he peak too early?

Gingrich has been pounded by incoming negative ad fire from Paul, Texas Gov. Rick Perry, and a super PAC supporting Romney, the former Massachusetts governor - all of it portraying Gingrich as an unreliable leader who has flip-flopped on conservative principles.

'Personal life'

Romney himself called Gingrich "zany" in a Wednesday interview with the New York Times, though he has mostly stayed above the fray.

Rick Santorum, the former Pennsylvania senator who has done more retail campaigning in Iowa than any of his rivals, made a veiled reference to Gingrich's three marriages and record of infidelity, warning that the GOP should make sure its nominee has no surprises lurking.

"We need someone who's strong in their political and personal life to go out and contrast themselves with the president," Santorum said.

For his part, Gingrich repeated that he was going to stay positive and not attack his peers. Of course, that's been situational.

When Romney was attacking Gingrich as a Washington insider in a debate Saturday, the former speaker retorted that "you would have been a career politician if you had beaten Teddy Kennedy" in 1994.

Bachmann attacked Gingrich for having said he would campaign for Republican politicians who did not support outlawing a form of late-term abortion known as "partial birth" abortion.

Gingrich said he has always opposed the procedure but was not interested in purging people from the GOP.

"I don't see how you're going to govern this country if you're going to run around deciding who you're going to purge," he said.

Perry compared himself to quarterback Tim Tebow of the Denver Broncos, known for dramatic wins and public displays of his Christian faith.

"There are people that stood up and said, 'Well, he doesn't have the right throwing mechanisms,' or 'He's not playing the game right,' " Perry said.

"And he won two national championships, and that looked pretty good. We were the national champions in job creation back in Texas. And so, am I ready for the next level?

"Let me tell you, I hope I am the Tim Tebow of the Iowa caucuses."

Former Utah Gov. Jon Huntsman, asked whether he was too moderate to galvanize Republican voters, responded with unusually strong language as he attacked the lack of trust in Wall Street and the dysfunctional government in Washington.

"We are getting screwed as Americans," said Huntsman, calling for congressional term limits. "I'm going to fix this country's trust deficit, because we're too good as a people to be in the hole we're in, and we deserve better."

Contact politics writer Thomas Fitzgerald at 215-854-2718 or tfitzgerald@phillynews.com or @tomfitzgerald on Twitter. Read his blog, "The Big Tent," at www.philly.com/BigTent.