Romney largely kept his criticism turned on President Barack Obama and the incumbent Democrat's handling of the economy, an issue that has blossomed anew as the GOP's top campaign concern in the wake of a tumultuous week on Wall Street and continuing high unemployment.
"I understand how the economy works," Romney said during the debate, noting the lessons of both successes and failures as a venture capital firm chief executive officer. "Our president doesn't understand how to lead or grow an economy."
He wouldn't bite when asked to comment on his rivals' economic positions.
And Romney's rivals gave him a pass on a potentially problematic comment he made earlier in the day at the Iowa State Fair when confronted by hecklers, who suggested corporations should pay more taxes. That prompted Romney to respond, "corporations are people."
Democrats quickly jumped on the exchange, though his GOP rivals did not.
Those who tried to knock him down a rung didn't even nick him.
Struggling to find traction, Pawlenty poked at Romney on several issues, including how much land he owns as well as his support for a Massachusetts health care bill similar to the national one Obama signed into law.
But Pawlenty ended up getting pulled into a family fight with Bachmann, who has outshone him in Iowa despite his 18 months of laying groundwork for a campaign.
"It's an undisputable fact that her record of accomplishment and results has been non-existent," Pawlenty said, adding: "She's got a record of misstating and making false statements."
Bachmann, who has eclipsed Pawlenty since entering the race, quickly responded with a list of what she called Pawlenty's liberal policies when he was Minnesota's governor, including his support for legislation to curb industrial emissions and his backing of an individual health care mandate in Minnesota, both unpopular positions with GOP activists.
"You said the era of small government is over," she told Pawlenty. "That sounds a lot like Barack Obama if you ask me."
Former Utah Gov. Jon Huntsman — making his first debate appearance — also tried to claim the space as the economic-focused candidate by championing his state's job gains during his tenure and noting his time as an executive in his family's chemical company. But Obama's former ambassador to China also defended his work under the Democratic president as well as his support for civil unions — both issues that are problematic in a GOP primary campaign.
Lesser-known candidates tussled for position, including former Pennsylvania Sen. Rick Santorum, Texas Rep. Ron Paul, businessman Herman Cain and former House Speaker Newt Gingrich.
Perry was absent from the stage. But not for long.
Thomas Beaumont covers the Republican presidential race for The Associated Press.
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