Former Minnesota Gov. Tim Pawlenty used the first Republican presidential debate — and the absence of major contenders — to showcase his credentials, deflect criticism of unpopular positions and introduce himself to voters.

The most newsworthy element of the Fox News-hosted forum held Thursday night in Greenville, S.C., might have been the number of likely candidates missing from the stage. The debate was the first of the primary season, but top contenders Mitt Romney and Newt Gingrich skipped it. Other potential candidates — including Mitch Daniels, Jon Huntsman, Donald Trump and Sarah Palin — stayed home.

Former Sen. Rick Santorum (Pa.); Rep. Ron Paul (Texas); former New Mexico Gov. Gary Johnson; and Herman Cain, who has never held public office, appeared with Pawlenty in Thursday’s debate.

One challenge Pawlenty faces is a lack of name recognition nationally, and he used the evening to tell his personal story and introduce himself to the voters tuning in to the still-forming race for the first time.

Pawlenty was put on the defensive when moderators presented him with a 2008 radio spot he recorded favoring a cap on greenhouse gases. The former governor told the audience he “made a mistake” and no longer supports a cap-and-trade system. “Nobody’s perfect,” he said.

Perhaps aware that he was the frontrunner onstage and that the evening carried low stakes, Pawlenty repeatedly detailed his record and reminded voters that he was from a working-class background. “I saw the face of job loss and economic worry in my hometown and even in my own family,” Pawlenty said.

The former governor mentioned several times that he grew up in a meat-packing town and worked in a labor union for seven years. “I understand this issue,” Pawlenty said when asked about the recent labor fight in Wisconsin. “We’re not against hardworking men and women. It’s not about bashing unions, it’s about being pro-job.”

He added that he balanced budgets over his eight years as governor and that he has been to Iraq five times and Afghanistan three times.

At one point in the debate, Pawlenty said, “As I get better known, I’m getting more and more support.”

In a testament to Pawlenty’s stature among his rivals on stage, the Democratic National Committee’s first two “fact-check” emails about the event were targeted at Pawlenty.

The moderators also asked Pawlenty about the health care plan Romney implemented during his time as governor of Massachusetts, but the Minnesotan declined to go after his rival. “I’m not going to pick on him,” he said.

Instead, Pawlenty mentioned Barack Obama’s January 2008 speech after his victory in the Iowa presidential caucuses. Obama had pledged to pass a health care program that would earn support from Republicans. “He broke that promise,” Pawlenty said.

Santorum, meanwhile, used most of his answers to sharply critique Obama on health care, spending and foreign policy.

The candidates discussed waterboarding, with Pawlenty and Santorum saying they would support the practice depending on the circumstances. Santorum credited such “enhanced interrogation techniques” for enabling the government to find al-Qaida leader Osama bin Laden.

Near that point in the debate, an audience member shouted, “It’s illegal!”

All of the candidates on the stage, with the exception of long-shot Cain, said they would have released the photos of bin Laden after he was killed.

Pawlenty praised Obama for making “tough decisions and being decisive” when it came to the bin Laden mission but added, “That moment is not the sum total of America’s foreign policy.”

Santorum credited President George W. Bush for bin Laden’s killing and said Obama has done right when he has continued Bush’s policies. He said Obama has gone wrong when he has set out on his own, and he specifically criticized the president’s handling of the political protests in Iran.

Paul, an anti-war libertarian with a grass-roots following, called for troops to be withdrawn from Afghanistan. He said that instead of spending “$1.5 trillion a year on our militarism,” the government should spend that money “back at home.”

Moderators asked Paul whether he was threatened by potential rival Rep. Michele Bachmann’s strength with the tea party. “She’s not here tonight,” Paul quipped about the Minnesota Republican.

Paul repeated his stance from his 2008 presidential campaign that he supports gay marriage. “The government should just be out of it,” Paul said. “They’ve caused more trouble than necessary.”

He earned applause for his stance on legalizing drugs, including heroin.

Moderators asked Santorum whether his desire to make English the nation’s official language could alienate Hispanic voters. The former Senator said he does not apologize for his position and said he believes it empowers immigrants to be integrated into society.

He also went after Obama for failing to pass immigration reform, given there was a solid Democratic majority on Capitol Hill during the first year of his presidency. “This is a political issue for the president,” Santorum said. “He’s playing political games with a very important group of people in America.”

Cain, the former CEO of Godfather’s Pizza, has been making the rounds courting tea party activists and said onstage that he supports a fair tax plan. He won the focus group hosted by Frank Luntz on Fox News following the debate.

Johnson is best known for his position favoring the legalization of marijuana, which he said he backed because it made sense for his state’s bottom line given high incarceration rates. “Everything was a cost-benefit analysis,” Johnson said. “Control it, regulate it, tax it.”

The Palmetto State will host a key early presidential primary in early 2012. No Republican nominee has claimed that prize without winning the South Carolina primary.