GOP presidential candidates will face off again at 8 p.m. ET next Tuesday in the CNN/Western Republican Presidential Debate in Las Vegas.
Hanover, New Hampshire (CNN) -- Herman Cain, the latest Republican presidential candidate to surge in the polls, found himself in the hot seat Tuesday night at a debate in New Hampshire centered on economic matters.
The linchpin of Cain's campaign, his cleverly titled 9-9-9 plan to restructure the U.S. Tax Code, came under harsh scrutiny as other Republicans sought to knock the former Godfather's Pizza CEO off his pedestal.
The Cain plan would implement a 9% corporate income tax rate, a 9% income tax rate and a 9% national sales tax.
His opponents called the plan unrealistic and said it stands zero chance of passing on Capitol Hill.
"I think it's a catchy phrase, in fact, I thought it was the price of a pizza when I first heard it ," former Utah Gov. Jon Huntsman joked. "We need something that's doable, doable, doable."
Two candidates competing with Cain for conservative voters in the leadoff caucus state of Iowa, former Sen. Rick Santorum of Pennsylvania and Rep. Michele Bachmann of Minnesota, sharply questioned Cain's economic credentials.
Santorum asked audience members at Dartmouth College to raise their hands if they support a new sales tax.
No one in the crowd appeared to do so.
"There you go, Herman. That's how many votes you'll get in New Hampshire."
He added, "Can we trust you with your lack of experience that you won't continually give Washington the ability to take freedom away from freedom-loving people?"
Bachmann said the plan would do little to create jobs and would simply offer the government a new way to collect tax revenue.
"When you take the 9-9-(9) plan and you turn it upside won, the devil is in the details," Bachmann said, a reference to 666, a symbol commonly associated with Satan.
Cain defended his plan as a fresh solution.
"Therein lies the difference between me, the nonpolitician, and all of the politicians," he said. "They want to pass what they think they can get passed rather than what we need, which is a bold solution."
Rep. Ron Paul of Texas also attacked Cain for naming former Federal Reserve Chairman Alan Greenspan as the kind of person he would appoint to the Fed if elected.
"Alan Greenspan was a disaster," Paul said, saying that Greenspan manipulated American currency and helped usher in the current economic crisis.
Former House Speaker Newt Gingrich attacked the current Federal Reserve chairman, Ben Bernanke, and said the central banking system should be subject to greater oversight.
"Bernanke has in secret spent hundred of billions of dollars bailing out one group and not bailing out another group," Gingrich said. "It is corrupt and wrong for one man to have that secret power."
Eight candidates participated in the economy-themed debate at Dartmouth College, sponsored by Bloomberg Television and The Washington Post. While some candidates trained their sights on Cain, others tried to sully former Massachusetts Gov. Mitt Romney, who has solidified his lead in national polls and in New Hampshire, a state central to his nomination strategy.
But as in previous debates, Romney, a tested campaigner, parried several attacks and kept the focus on jobs and the economy.
In one portion of the debate, moderators allowed the candidates to ask questions of one another.
Texas Gov. Rick Perry pressed Romney on his health care overhaul in Massachusetts, which he compared to Obama's national plan.
Romney turned the question around on Perry.
"We have less than 1% of our kids that are uninsured," Romney said. "You have a million kids uninsured in Texas. A million kids. Under President Bush, the percentage uninsured went down. Under your leadership, it's gone up."
Perry, who has been criticized by Romney for not outlining a detailed economic plan, said he would begin rolling out a platform in the coming days, beginning with a speech this week on boosting domestic energy production.
"It's time for another American declaration of independence," Perry said. "It's time for energy independence."