Herman Cain announced today that he is tweaking his 9-9-9 plan. The old version would have replaced the current tax code with a 9 percent sales tax, a 9 percent income tax, and a 9 percent business tax. The new version creates a special exemption for families in poverty. Cain would remove the income tax, making it, effectively, a 9-0-9 tax, which is at least a cozy number for San Bernadino Country Republicans. He would also create special business tax breaks for economically distressed districts.

According to the Tax Policy Center, a 9-0-9 tax would still raise rates on the poorest households. The center's first pass at Cain found his plan would raise taxes for 84 percent of Americans while handing out huge tax breaks to millionaires thanks to a zero percent tax on investment income. Households making less than $50,000 would lose an extra two months' worth of income. Millionaires would see their after-tax haul increased by more than a quarter.

The 9-0-9 corollary is a first step toward a plan with so many numbers, it's no longer worth running in a headline or campaign brochure. As long as Cain competes (and he's currently polling first in Iowa), he's going to be under pressure to create special exemptions in what began as an exemption-free tax code.