Watch a replay of Saturday's ABC/WMUR Republican presidential debate at 8 p.m. ET on CNN.
Manchester, New Hampshire (CNN) -- It didn't take long for fireworks to erupt at Saturday night's Republican presidential debate.
But while most of six candidates on the stage at Saint Anselm College traded barbs, Mitt Romney didn't field much incoming fire from his rivals, and didn't apparently do any damage to his front-runner status in the race for the GOP nomination.
About the worst of it came early, when Romney was questioned about his involvement in laying off workers at companies acquired by Bain Capital, a private equity firm he steered.
"It always pains you if you have to be in a situation of -- of downsizing a business in order to try and make it more successful, turn it around and try and grow it again," Romney said.
The former Massachusetts governor, who often touts his business and corporate experience as he makes his second bid for the White House, was also targeted early in the showdown by former Sen. Rick Santorum of Pennsylvania, who said that "business experience doesn't necessarily match up with being the commander in chief of this country. The commander in chief of this country isn't a CEO."
Romney defended himself, saying, "I think people who spend their lives in Washington don't understand what happens in the real economy. They think the people who start businesses are just managers. People who start as entrepreneurs, who start businesses from the ground up, getting investors and hiring people to join them, those people are leaders."
With three days to go until New Hampshire's primary, the second contest in the primary and caucus calendar, Romney holds a large lead over his rivals in the latest polls in the Granite State. He also holds a double digit advantage over the rest of the Republican presidential candidates in a new CNN/Time/ORC International survey in South Carolina, which holds its primary 11 days after New Hampshire.
The ABC News/WMUR-TV showdown was the first debate in three and a half weeks, a lifetime in this campaign cycle. Since the last debate in Iowa in mid-December, former House Speaker Newt Gingrich's has seen his poll numbers plunge, while Santorum, once an afterthought in the battle for the nomination, has seen his numbers surge. But a rise in the polls brings more scrutiny.
"He's a big government person, along with him being very associated with the lobbyists and taking a lot of funds, and also, where did he make his living afterwards? He became a high-powered lobbyist in Washington, D.C.," charged Rep. Ron Paul of Texas, who's making his third run for White House.
Santorum, who came in an extremely close second to Romney in Tuesday's Iowa caucuses, fired back, saying "it's a ridiculous charge, Ron. I'm a conservative, not a libertarian. I believe in some government."
The action became deeply personal when Paul repeated his charge that former House Speaker Newt Gingrich was a "chicken hawk" who avoided military service. Paul said Gingrich had obtained several deferments to stay at home with his family.
"I'm trying to stop the wars but at least I went when they called me up," said Paul, who served as a surgeon in the Air Force. "When I was drafted, I was married and had two kids, and I went."
Gingrich, the one-time front-runner in the polls, snapped back, pointing out that "I wasn't eligible for the draft. I wasn't eligible for the draft."
He also cited his father's military service and accused Paul of having a "long history of saying things that are false."
"I think I have a pretty good idea of what it's like as a family to worry about your father getting killed and I personally resent the kinds of comments and aspersions he routinely makes without accurate information and then just slurs people," Gingrich said.
Gingrich finished a disappointing fourth in the Iowa caucuses. Texas Gov. Rick Perry finished fifth.
Perry made news at the debate, saying he would support sending troops back into Iraq. U.S. forces completed their pullout from Iraq last month after eight years of war. But Perry predicted that neighboring Iran would reenter Iraq without American troops there to defend the country.
"They're going to move back in and all of the work we've done, every young man that has lost his life in that country would have been for naught because we've got a president who does not understand what's going on in that region," Perry said.
It was one of the few times the candidate differentiated himself from his rivals, none of whom have suggested sending U.S. forces back into Iraq. Nearly eight out of 10 Americans said they approved of the U.S. pullout from Iraq, according to a CNN/ORC International poll conducted last month.
Former Utah Gov. Jon Huntsman was also on the stage at the ABC News/WMUR-TV debate. Huntsman, who served under President Barack Obama as ambassador to China, said "I think I understand better than anyone on this stage, the complex national security implications that we will face going forward with what is, we all know, the most complex and challenging relationship of the twenty first century, that of China."
Romney, leaning forward and staring at Huntsman, said "I"m sorry, governor, the past two years you were implementing the policies of this administration in China."
Tuesday's primary is widely thought to be a make-or-break moment for Huntsman. He's spent virtually all of his time campaigning in New Hampshire, and is counting on a strong showing to continue his longshot bid for the White House.
The showdown is the first of two debates this weekend. The six candidates face off again Sunday morning in Concord, New Hampshire, on NBC's "Meet the Press."
Just 10 hours will separate the two debates, a one-two punch that will afford voters their last chances to weigh their choices ahead of decision day next week.
CNN's Gabriella Schwarz, Shawna Shepherd and Shannon Travis contributed to this report.