Is Herman Cain's 9-9-9 tax plan fair?

WASHINGTON -- Herman Cain's standing in the polls in the race for the Republican presidential nomination has risen with the growing popularity of his 9-9-9 tax plan, which has become such a signature issue for the former pizza company executive that the crowds who come to see him speak routinely cheer at its mention.

The plan, which calls for a 9% income tax, 9% national sales tax and 9% corporate income tax, would create tax equality and stabilize federal finances, Cain said.

"And it'll save all of us, collectively, $430 billion a year that we spend to fill out the stupid tax code — 9-9-9," Cain said at a speech in Washington last week.

Not so fast, say tax experts from all parts of the political spectrum. While Cain's plan has an appealing simplicity to Americans frustrated with the nation's labyrinthine tax system, it would dump a much heavier tax burden on low-income citizens.

Cain's campaign has not released enough specifics about the plan to determine whether it is progressive or regressive, said Will McBride, an economist with the nonpartisan Tax Foundation, but "any sort of movement to a consumption tax, which this is with the sales tax, is a move away from progressivity."

"Warren Buffett can't reasonably spend $40 million a year on consumption," he said. "It just happens that folks that make more money, they consume less of their income."

For the 46% of Americans who did not pay income tax last year, the 9% tax would mean an automatic increase, said Roberton Williams, a senior fellow at the non-partisan Urban Institute.

Even the elimination of the payroll tax for Social Security benefits would not be enough to prevent a tax increase for lower-income Americans, Williams said. That's because 23% of taxpayers pay no taxes or get a tax credit greater than the payroll tax, he said.

Meanwhile, Williams said, wealthier Americans would get a tax cut. "On the top end, 9% is a lot better deal than what people at the top end are paying," he said, adding that the Urban Institute estimates that those who make more than $1 million pay 18% in personal income taxes.

"Going to 9% is going to save them half; that's a nice savings," Williams said. "That's the income tax side: The rich will pay less; the poor will pay more."

Cain's plan would remove tax credits that help lower-income Americans, said Steve Wamhoff, legislative director for the left-leaning Citizens for Tax Justice. Those lost credits would include the earned income tax credit and child tax credit, Wamhoff said. "That stuff would all be lost with Herman Cain's plan," he said.

Cain defended the plan during a speech Friday in Washington, saying his ascent to "top tier" candidate status has put a "bull's-eye" on his back.

"Well, see, the critics are already trying to try and prove why 9-9-9 is not a good idea," he said. "When you see some of these reports talking about it won't do this and it won't do that and it won't do this and it won't do that, they have changed the assumptions. If you want to know what the assumptions are, why don't you come to me and my people, and we'll explain to you what the assumptions are. But they don't want to do that."

Cain's campaign did not return a request for comment.

It's also uncertain whether a consumption-based tax can coexist "alongside an income tax, no matter how low the rates," said Mike Franc, vice president of government studies for the conservative Heritage Foundation.