A blank drawn by Texas governor Rick Perry during questioning was the main talking point in the Republican's presidential debate last night.
The Rochester, Michigan, debate also saw Republican rivals hold their fire over sexual harassment allegations threatening rival Herman Cain's White House bid.
Mr Perry, who has seen his poll standing plummet after several poor debate performances, had another disastrous moment when he completely blanked on naming the third federal agency he wants to shut down.
Despite helpful suggestions from some of his rivals, Mr Perry could not name the third agency after Education and Commerce. "Sorry," he said.
A little later in the debate he thought of the answer - the Department of Energy. "Yeah, it was embarrassing, of course it was," Mr Perry told reporters in a rare post-debate appearance in the media room. "But people understand our conservative principles are what matter."
Mr Cain, a former pizza executive who leads some polls in the race, faced only one question about the accusations by four women dating to the late 1990s. Main rival Mitt Romney refused to wade into the controversy.
"The American people deserve better than someone being tried in the court of public opinion based on unfounded accusations," Mr Cain said in the debate at Oakland University.
He has denied the harassment charges and noted the issue had not dented voter enthusiasm for his campaign to face President Barack Obama, a Democrat, in the November 2012 election. "They don't care about character assassination, they care about leadership and getting the country going," he said to cheers from the audience.
The allegations include one from a woman who said Mr Cain groped her in 1997 when he was head of the National Restaurant Association.
The controversy has lingered for more than a week and eroded favourable voter perceptions of Mr Cain, but he is still running close at the top of the pack with Mr Romney, a former governor of Massachusetts.
Mr Cain's difficulties could open the door for one of the other candidates battling for the allegiance of conservatives in the hopes of becoming the clear alternative to the more moderate Mr Romney.
Mr Cain raised some eyebrows in the debate when he described former House speaker Nancy Pelosi as "Princess Nancy", a remark he later said he regretted.
The moderator's question about the allegations drew boos from the audience at the debate, which was focused on economic issues. Mr Romney was cheered when he declined to answer when asked if he would hire an executive facing similar charges.
Mr Romney faced his own character question during the debate, rejecting accusations that have plagued him since his failed 2008 presidential campaign that he has flip-flopped on crucial issues including the US car industry bailout in 2009.
"I think people understand that I'm a man of steadiness and constancy," Romney said. "I don't think you are going to find somebody who has more of those attributes than I do."
Mr Romney's past support for abortion rights and a healthcare mandate while governor of Massachusetts - he now opposes both - still makes him an object of suspicion for many social and religious conservatives.
Many of the Republican hopefuls denounced government bailouts for corporations and other countries and said they would not come to the financial rescue of Italy, which is struggling to bring its debt under control.
"It doesn't make any difference whether it's Wall Street or some corporate entity or some European country - if you are too big to fail, you are too big," Mr Perry said.
Reuters