IOWA CITY — Three Republican presidential hopefuls clawing for top-three Iowa caucus finishes assailed Newt Gingrich from the right, during a two-hour, seven-candidate debate Thursday night in staunchly Republican western Iowa.

A contentious question about partial-birth abortion provoked Gingrich, the former speaker of the U.S. House of Representatives, to lash out at opponent Michele Bachmann for "consistently getting her facts wrong," in one of the most heated moments of the night.

"I'm a serious candidate for president of the United States, and my facts are accurate," Bachmann, a Minnesota congresswoman, spit back.

Former Pennsylvania U.S. Sen. Rick Santorum used his opening lines in the Sioux Center Convention Center to take a swing at Gingrich, a former Georgia congressman.

"The speaker had a conservative revolution against him when he was the speaker of the House," said Santorum, who represented Pennsylvania for 16 years on Capitol Hill. "I had conservatives knocking down my door because I was the effective advocate for the principles that they believed in. That's the contrast."

Texas Gov. Rick Perry dinged Gingrich for his private sector career, saying "the idea that you can't tell the difference between lobbying and consulting" was one of his biggest inspirations for a plan to overhaul Washington, D.C.

Perry's well-funded campaign fired a barrage of attack ads at former Massachusetts Gov. Mitt Romney, a persistent frontrunner, and Gingrich this week. Perry has sought to brand the pair as "Washington insiders."

In an attempt to redeem his rocky debate reputation, Perry delivered the laugh line of the night: "I want to be the Tim Tebow of the Iowa caucuses," he said.

Tebow is a National Football League quarterback who has helped the Denver Broncos pull off close victories late in the game.

With less than three weeks to go until the Jan. 3 Iowa caucuses, Bachmann, Perry and Santorum could use a political comeback in Iowa, where they are languishing in the single digits in public opinion polls.

Bachmann and Santorum also lashed out Texas U.S. Rep. Ron Paul, who has one of the strongest grassroots organizations in Iowa.

"I think I have never heard a more dangerous answer for American security than the one I just heard from Ron Paul," Bachmann said during a debate about Iran, in which Paul suggested the U.S. try diplomacy, rather than war in the Middle East.

Her statement drew a mixture of cheers and boos from the audience.

It remains to be see if bloodying two of the frontrunners — Gingrich and Romney — can launch Bachmann, Santorum or Perry, who have been vying for endorsements from the region's influential evangelical pastors, into the top tier.

Romney spent the majority of the debate attacking President Barack Obama.

"Our president thinks America's in decline," he said. "It is if he's president, not if I'm president."

Democrats said all the Republican candidates seemed to be focused on attacking one another, rather than laying out positive policy solutions.

Iowa Democratic Party Chairwoman Sue Dvorsky said the candidates are "clawing over each other to get to the right of the one standing next to them, until they've brought the entire process over a cliff."

Romney had a dust-up with the Santorum and Bachmann over same-sex marriage.

"I do not believe in discriminating against people because of their sexual orientation," Romney said, when asked by FOX News moderators to explain his stance on social issues. Fox News co-sponsored the debate with the Republican Party of Iowa, .

Santorum interjected, saying, "We're not talking about discrimination. We're talking about a fundamental change to our moral values."

Former Utah Gov. Jon Huntsman also attended Thursday night's debate, though he is not actively campaigning in advance of the Iowa caucuses.

Santorum hit Iowa airwaves Thursday afternoon with the first TV ad of his shoestring presidential campaign — a 30-second spot boasting support from 2008 Iowa Caucus winner Mike Huckabee and former Republican vice presidential nominee Sarah Palin.

Going into the final weeks of the campaign in Iowa, Bachmann launches a "barnstorming bus tour" of Iowa's 99 counties, on Friday morning. It is a campaign technique employed much earlier by Santorum.

Hannah Hess covers government and politics for, which is owned by the Frankling Center for Government and Public Integrity.