Eight Republicans seeking to capture the White House in 2012 attacked the current occupant -- and each other -- in a fiery debate Thursday, but the GOP front-runner, former Massachusetts Gov. Mitt Romney, though somewhat sidelined, only needed to hold his ground.
Romney comes out of the debate looking to keep his position at the top of the pack, as the candidates head into the nonbinding, but influential Iowa Straw Poll this weekend.
The race is still wide open, especially with Texas Gov. Rick Perry ready to enter the fray on Saturday.
The two candidates hailing from Minnesota led off the slugfest Thursday night.
Former Minnesota Gov. Tim Pawlenty, who is seeking to boost his flagging campaign, dismissed Minnesota Rep. Michele Bachmann in the debate, dismissing her record of accomplishments and results in Congress as "nonexistent."
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"That's not going to be good enough for our candidate for president of the United States," he said. "The American people are going to expect more and demand more. And in fact we need somebody who can contrast with Barack Obama on results."
Bachmann fired back that Pawlenty's actions as governor, including his support for legislation to curb emissions and the individual mandate in health care, "sounds a lot like President Obama."
"During my time in U.S. Congress, I have fought all of these unconstitutional measures," she said.
Pawlenty replied that Bachmann has a record of misstating and making false statements. He also questioned her fighting skills, saying that her efforts to prevent more government spending, to derail "Obamacare" and to stop government bailouts after the 2008 financial crisis didn't work.
"She says she's got a titanium spine. It's not her spine we're worried about, it's her record of results," he said. "If that's your view of effective leadership with results, please stop because you're killing us."
Texas Rep. Ron Paul and former Pennsylvania Sen. Rick Santorum also clashed during Thursday's debate, over Iran's nuclear ambitions and its threats to the United States.
Paul said Santorum engages in "war propaganda." Santorum said Paul is "obviously not seeing clearly" on the subject and does not understand the threats to the country from Islamic militants.
Fox News, the Washington Examiner and the Iowa Republican Party sponsored the two-hour nationally televised debate.
The debate capped off an eventful day in which Romney took on a liberal heckler and Perry, who was not on the debate stage, revealed he was joining the GOP race.
Candidates kicked off Thursday's debate by attacking Obama's economic record.
"If you spend your life in the private sector, you understand what President Obama has done is the complete opposite of what needs to be done," Romney said in response to how he would turn the economy around.
But Pawlenty later put Romney on the defensive about the health care program he signed into law in Massachusetts for its similarities to Obama's signature initiative -- an opportunity he passed up in the previous debate.
"Obamacare was patterned after Mitt's plan in Massachusetts, and for Mitt or anyone else to say they're not essentially the same plan, it just isn't credible. And that's why I called it Obamneycare and I think that's a fair label," he said.
Pawlenty also attacked Romney's record on spending and judicial appointments as governor.
Romney replied by joking that he liked Pawlenty's answer in the last debate better, drawing laughs. Romney then defended his health care program, acknowledging there are similarities but also differences, using a states-rights argument.
"We put together a plan that was right for Massachusetts. The president took the power of the people and the states away from them and put in place a one-size-fits-all plan," he said, adding that he would grant all 50 states a waiver from that law if he is elected.
Other candidates struggled to get as much attention.
Nearly an hour into the debate Santorum raised his hand and said: "I haven't gotten to say a lot."
Jon Huntsman, making his presidential debate debut, admitted he had not offered an economic plan but cited his economic record as governor of Utah as evidence of what he would accomplish as president. He also defended his service as ambassador to China under Obama.
Former House Speaker Newt Gingrich, pressed on the apparent implosion of his campaign amid financial strife and infighting earlier this summer, chastised the debate panel for "gotcha questions." He said Republicans including Ronald Reagan and John McCain had staff defections during their campaigns, and he said he intended to "run on ideas."
Businessman Herman Cain, meanwhile, pitched himself as the best choice for improving the economy.
"It is clear from the discussion tonight that America needs a leader and a uniter," he said. "I represent growth. All the issues that we talk about, if we don't get this economic engine moving by putting fuel in the engine, all of the rest of it won't matter."
Showing the wide diversity of opinion, Paul gave a staunchly libertarian answer to nearly every question from the economy to foreign affairs, essentially saying the United States should have friendly relations even with countries that violate human rights and not interfere in their internal affairs.
"It's about time we talk to Cuba," Paul said at one point. He also said the United States had created the hostile relations between it and Iran.
The Associated Press contributed to this report.