If Herman Cain wondered what his future would be like now that he has reached the upper levels of the GOP race for the White House, the new reality was brought home by the first question of Tuesday night's debate, which turned into a party-wide smackdown of his economic plan.

"Go to New Hampshire where they don't have a sales tax," said Gov. Rick Perry sternly to Cain, "they're not interested in 9-9-9."

"Gov. Perry was right," said Mitt Romney.

"No, he wasn't," Cain shot back, accusing his critics of "mixing apples and oranges."

"But will the people of Nevada not have to pay Nevada sales tax, in addition to the 9% sales tax?" Romney asked, knowing full well the answer was 'Yes.'

"Middle income people see higher taxes under your plan," as Romney joined the five others on stage in a very public rebuke of Cain's campaign centerpiece.

Cain sharply disputed the attacks against 9-9-9, saying that other candidates were ignoring his own analysis.

"Nine percent more? I don't think so, Herman," said Perry. "It's not going to fly."

Even Newt Gingrich, who has resisted slashing attacks on his competition gave his fellow Georgian a rap on the wrist as well.

"You have said in recent days that Herman Cain's 9-9-9 plan would be a harder sell," said CNN moderator Anderson Cooper to Gingrich.

"How so?" asked Cooper.

"Well, you just watched it," Gingrich observed dryly, sparking loud laughter from Michele Bachmann and others.

While Cain said afterward that he felt like the line of questioning was somewhat unfair, he plowed ahead, refusing to give an inch to his critics.

"You're absolutely wrong," Cain said at one point.

As the debate went forward, Cain salved his wounds and found his voice later on, turning a question from Cooper about the Occupy Wall Street demonstrators into a big applause line.

"They oughta be over in front of the White House taking out their frustration," said Cain.

Cain was forced to backtrack later in the debate on a statement he had made earlier in the day, when he said he would be open to negotiations with terror groups if they were holding U.S. soldiers.

Cain denied making the statement, but when it was replayed for him by Cooper after the debate, he simply said he had made a mistake and that he would never negotiate with hostages about anyone being held at Guantanamo Bay.

For Cain supporters, that type of admission is one reason they like him - he's not like "other" politicians as he often points out.

But those "other" politicians also can sense some blood in the water on 9-9-9, and for now, they seem unlikely to let up on Cain, arguing that his plan would only raise taxes on working families.

Now that Cain is in the big leagues, he may face more verbal barrages like this one - as it seems unlikely that this 9-9-9 attack will stay in Las Vegas.