Minnesota Republicans Tim Pawlenty and Michele Bachmann, making their first joint appearance as presidential candidates, provided two of the dramatic highlights of the GOP presidential debate in New Hampshire Monday night.

Bachmann, the only woman on the stage, took over the spotlight with a surprise announcement that she had filed legal papers with the Federal Election Commission for a presidential bid.

Meanwhile, Pawlenty found himself awkwardly backing away from a pre-debate swipe in which he had coined the term "ObamneyCare" to highlight the similarities between the federal health care mandates and the program front-runner Mitt Romney had created as governor of Massachusetts.

So began the first high temperature crucible of the 2012 presidential election, a crucial test for the seven candidates who took part in the debate at St. Anselm College in Manchester.

For Bachmann and Pawlenty, the first debate of the first-in-the-nation New Hampshire primary was a chance to make a statement. Neither one waited for the debate to start.

Bachmann, a Tea Party superstar, arrived after making a splash in the Wall Street Journal, which asked her whether Pawlenty, her main rival in Iowa, was a good governor.

"I really don't want to comment," she replied in an article posted to her Facebook page.

Pawlenty, taking aim at Romney, whom he needs to unseat as front-runner, gave an interview to Fox News Sunday where he first used the term "ObamneyCare."

But the quip came back to bite Monday night when CNN moderator John King pressed him to repeat the phrase to Romney outside "the comfort of a Sunday show studio."

Pawlenty, appearing visibly uncomfortable, said the term was "a reflection of the president's comments that he designed ObamaCare on the Massachusetts health care plan."

Romney, asked to respond, declined to engage Pawlenty directly, noting instead the differences between federal and state mandates and adding that Obama never consulted him.

"Ours was a state plan, a state solution," Romney said.

As she has on the stump, Bachmann made repealing Obama's health care law her signature issue. "I will not rest until I repeal ObamaCare," she said. "It's a promise. Take it to the bank. Cash the check. I'll make sure that that happens."

She also gave an impassioned defense of the Tea Party movement which makes up her core base of support. "It's a wide swath of America coming together," she said. "That's why the left fears it so much."

Neither Bachmann, who introduced herself as a mother and a tax attorney, nor Pawlenty, who introduced himself as a father and "neighbor," arrived on the stage unbloodied. Romney's camp had already fired back at Pawlenty through a pre-debate tweet by spokesman Eric Fehrnstrom, who noted that as governor, Romney left behind $2.3 billion "in cash for his successor."

The statement didn't mention Pawlenty, but it clearly begged for comparisons with the Minnesota governor, who left office in January with a $6.2 billion projected deficit.

The criticism was picked up by the New Hampshire Democratic Party, which released a Web ad attacking Pawlenty's fiscal record in Minnesota, a theme that will likely loom large if he wins the GOP nomination to challenge Obama in the general election next year.

As he did in the first GOP debate in South Carolina in May, when he was the only major candidate to participate, Pawlenty went into the debate disavowing the state budget shortfall, attributing it to current spending decisions for which he is not to blame.

Pawlenty also was called on to defend his recently announced economic plan of deep tax and spending cuts, which has been criticized for a 5 percent growth target that many economists find unrealistic.

"We're not the same as Portugal, we're not the same as Argentina," Pawlenty said. "This idea that we can't have 5 percent growth in America is hogwash. It's a defeatist attitude."

Romney, as front-runner, kept his focus on Obama rather than Pawlenty. "Tim has the right instincts," said Romney, pivoting from a question about Pawlenty's plan to a blast at the shortcomings of the economy under Obama. "The president has failed."

Pawlenty's exchange with Romney highlighted the dynamics of a multi-candidate debate that analysts see as dividing into two tiers.

In the early going of the GOP nomination contest, Romney and Pawlenty, along with former House Speaker Newt Gingrich, have been treated as establishment candidates vying for the same insider credibility and general election appeal.

Bachmann and the other three candidates in the New Hampshire debate -- former Pennsylvania Sen. Rick Santorum, Texas Rep. Ron Paul and businessman Herman Cain -- are viewed as conservative mavericks with outsider appeal.

Two other names looming large in the GOP contest, former Alaska Gov. Sarah Palin and former Utah Gov. Jon Huntsman, have not declared their candidacies and did not take part on the debate. Also in the wings: Texas Gov. Rick Perry.

For Pawlenty, who has been polling in the single digits, Monday's debate was a chance to outshine Romney, who lost the 2008 GOP nomination to Sen. John McCain.

Bachmann, making her first appearance in a nationally televised presidential debate, had to translate a record of provocative media appearances, and sometimes gaffes, into a presidential image. She said she would make a formal announcement "very soon."

Kevin Diaz is a correspondent in the Star Tribune Washington Bureau.