Herman Cain received the lion’s share of attacks in the early stages of the Las Vegas CNN Republican debate on Tuesday night, as Mitt Romney, Rick Perry and several other candidates criticized his 9-9-9 tax plan. As Karen Tumulty and Amy Gardner reported:

The near-weekly ritual of Republican presidential debates took a raucous turn Tuesday night as the unsettled field of candidates ganged up on one another in a series of attacks more intense and personal than any in their previous appearances together.

The first to feel the assault was the front-runner of the moment, Herman Cain, who is struggling to prove that he is a serious contender and not merely another evanescent phenom of this election season. He was thrown on the defense by new criticism of his signature “9-9-9” tax overhaul plan, which an independent analysis released shortly before the debate indicated would be a boon to the wealthy and put a significantly heavier burden on lower- and middle-income Americans.

Of all the candidates to emerge from the pack in this volatile election cycle, Cain has been the most unlikely. His precarious position at the top of the field was made all the more so by a new study issued Tuesday by the nonpartisan Tax Policy Center on his 9-9-9 plan.

He has said that the plan would reduce taxes for most Americans, but the center said otherwise.

According to the analysis, Cain’s proposal would lower taxes for 95 percent of the nation’s millionaires an average of $487,000. The vast majority of taxpayers earning less than $100,000 would bear a tax increase.

Asked about the review of his plan — which would replace the current tax system with a 9 percent levy on individual income, corporate earnings and purchases — Cain dismissed it as a “knee-jerk reaction” that was refuted by his campaign’s calculations.

A review of his 9-9-9 tax plan reveals that while many of the wealthy would get a tax break, a majority of households would see their tax burden rise. As AP related:

Herman Cain’s 9-9-9 tax plan would raise taxes on 84 percent of U.S. households, according to an independent analysis released Tuesday, contradicting claims by the Republican presidential candidate that most Americans would see a tax cut.

The Tax Policy Center, a Washington think tank, says low- and middle-income families would be hit hardest, with households making between $10,000 and $20,000 seeing their taxes increase by nearly 950 percent.

“You’re talking a $2,700 tax increase for people with incomes between $10,000 and $20,000,” said Roberton Williams, a senior fellow at the Tax Policy Center. “That’s huge.”

Households with the highest incomes, however, would get big tax cuts. Those making more than $1 million a year would see their taxes cut nearly in half, on average, according to the analysis.

Among those in the middle, households making between $40,000 and $50,000 would see their taxes increase by an average of $4,400, the report said. Those making between $50,000 and $75,000 would see their annual tax bill go up by an average of $4,326.

Cain’s answers when asked whether he would release prisoners from Guantanamo Bay in exchange for the release of a U.S. soldier also came under fire, and could cause problems for the candidate in the future. As Rachel Weiner explained :

Foreign policy has never been Herman Cain’s strong suit. But his response in the Las Vegas debate on the possibility of exchanging a soldier for Guantanamo Bay prisoners can’t be good for the former Godfather’s Pizza CEO.

Not only did Cain contradict himself, he was forced to admit that he made a mistake and did not understand a question.

“I could see myself authorizing that kind of transfer,” Cain told Wolf Blitzer Monday afternoon when asked if he would free all the prisoners in Guantanamo Bay in exchange for one American hostage. “I would make sure that I got all of the information, I got all of the input, considered all of the options. ... I could make that call if I had to.”

The question stemmed from Israel’s decision to free 1,027 Palestinian prisoners in a swap with the militant group Hamas for one captured soldier.

In the CNN debate later in the evening, Cain appeared to not remember the question in detail. “I don’t recall him [Blitzer] saying that it was al Qaeda-related,” he said. Blitzer had described an “al Qaeda or some other terrorist group.

“My policy would be we cannot negotiate with terrorists. That’s where we have to start as a fundamental principle,” Cain continued. “I would never agree to letting hostages in Guantanamo Bay go. That wasn’t the intent at all.”

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