Minnesota rivals Tim Pawlenty and Michele Bachmann have sparred bitterly in a Republican presidential debate, trying to stand out ahead of an Iowa test vote with huge consequences.
Each seeks to become the main challenger to Republican front-runner Mitt Romney.
In the two-hour, eight-candidate debate, the squabbling by Mr Pawlenty and Mrs Bachmann allowed Mr Romney to remain above the fray and emerge relatively unscathed by his rivals.
Their efforts to earn the right to face President Barack Obama were newly complicated by Texas Governor Rick Perry, who stole some of the spotlight from afar by making it known hours before the debate that he was running for the Republican nomination.
Mr Romney, a multimillionaire businessman who casts himself as a jobs creator, made his own stir earlier in the day when, at the Iowa State Fair, he declared that "corporations are people", drawing ridicule from Democrats.
Those were just the latest twists in the most consequential week yet in the 2012 Republican presidential nomination fight. Seven candidates - Mr Pawlenty, Mrs Bachmann, former Utah Governor Jon Huntsman, former House Speaker Newt Gingrich of Georgia, Texas Representative Ron Paul, former Pennsylvania Senator Rick Santorum and businessman Herman Cain - sought to separate themselves from the packed field and emerge as the chief alternative to Mr Romney.
Though every debate participant assailed Mr Obama, it was clear from the confrontations between Mr Pawlenty, a former Minnesota governor, and Mrs Bachmann, now a member of Congress, who had the most on the line ahead of Saturday's test vote that could well reduce the field.
Mr Pawlenty, who is struggling to gain traction despite spending years laying the groundwork for his campaign, accused Mrs Bachmann of achieving nothing significant in Congress, lacking executive experience and having a history of fabrications. "She's got a record of misstating and making false statements," Mr Pawlenty said.
Mrs Bachmann, who has risen in polls since entering the race this summer and has eclipsed Mr Pawlenty, quickly responded with a list of what she called Mr Pawlenty's liberal policies when he was Minnesota's governor, including his support for legislation to curb industrial emissions. "You said the era of small government is over," she told Mr Pawlenty. "That sounds a lot like Barack Obama if you ask me."
Much of the rest of the debate was heavily focused on the Democratic incumbent, with Mr Romney and his seven rivals each seeking to prove he or she was the strongest Republican to take on Mr Obama. "I'm not going to eat Barack Obama's dog food," Mr Romney said when asked whether he would have vetoed the compromise legislation that Congress gave to the president that raised the debt ceiling. "What he served up is not what I would have done if I'd had been president of the United States."