Looking for a comeback in the GOP presidential race, Minnesota Republican Michele Bachmann sparred aggressively Thursday night with front-runner Newt Gingrich and libertarian favorite Ron Paul, her top rivals in the Iowa caucuses on Jan. 3.

It was a sharp exchange with Gingrich, the former House Speaker who accused her of getting her facts wrong, that produced a particularly testy rebuttal from Bachmann.

"I think it's outrageous to say over and over in the debates that I don't have my facts right, when as a matter of fact I do," said Bachmann, showing exasperation at the frequent criticism of her command of facts. Asserting herself as the only woman on the debate stage, Bachmann added, "I'm a serious candidate for president of the United States, and my facts are accurate."

The face-off was prompted by a dispute over abortion, in which Bachmann faulted Gingrich for backing candidates who support partial-birth abortion, a practice she termed "barbaric." Gingrich bristled at the accusation, noting that all he had ever said was that "I wouldn't go out there and purge Republicans."

The two also mixed it up over Gingrich's past as a consultant for embattled housing giant Freddie Mac. Asked for hard evidence to back up her charge that Gingrich had engaged in influence peddling, Bachmann shot back, "We know he cashed paychecks from Freddie Mac, that's the best evidence that you can have." Given a chance to respond in the last debate before the Iowa caucuses, Gingrich took his first of several swipes at Bachmann's reputation for playing loose with the facts. "That's just not true," he said. "What she just said is factually not true. I never lobbied under any circumstance…Sometimes people ought to have facts before they make wild allegations." But Bachmann got the floor again in the Fox debate in Sioux City, providing some of the night's most spirited moments. "The evidence is that Speaker Gingrich took $1.6 million," she said. "You don't need to be within the technical definition of being a lobbyist to still be influence-peddling with senior Republicans in Washington, D.C., to get them to do your bidding, and the bidding was to keep this grandiose scam, Freddie Mac, going. That is something our nominee can't stand for." Gingrich said that he now favors breaking up Fannie Mae and Freddie Mac. Then, turning the subject slightly, he added, "I have never once changed my positions because of any kind of payment… The fact is I only chose to work with people whose values I shared, and having people have a chance to buy a house is a value I believe still is important in America." In a prolonged exchange with Paul that featured a lot of interruption and cross-talk, Bachmann accused the Texas congressman of taking a "dangerous" tack by downplaying the danger of an Iranian nuclear bomb. Paul accused Bachmann and other GOP contenders of warmongering. Bachmann's campaign also took aim at establishment front-runner Mitt Romney, who acknowledged that he has changed his mind on abortion. "Romney said he changed his mind on life," tweeted Bachmann spokeswoman Alice Stewart. "Who's to say he won't change it back?"