Republican presidential candidate Herman Cain's 9-9-9 tax plan has taken a lot of heat recently. One of the biggest criticisms: several independent analysts have found that under the plan, poor and middle class families would pay higher taxes while the richest of the rich would see a substantial tax cut. Today in Detroit, Cain unveiled his response.

"If you're at or below the poverty level, your plan isn't 9-9-9," said Cain with the abandoned Michigan Central Station in the background. "It's 9-0-9."

Republican presidential candidate Herman Cain's much discussed 9-9-9 tax plan just got a major facelift after intensifying criticism that it would shift the tax burden to the least fortunate Americans.

In a Detroit speech Friday, the former Godfather's Pizza CEO created another numbers scheme for those "at or below poverty level."

"Your plan isn't 9-9-9," Cain said, addressing low-income voters. "It is 9-0-9."

"Say amen y'all," said Cain, also a Baptist minister. "9-0-9."

This past week, republican presidential candidate Herman Cain has been hit hard over his 9-9-9 tax overhaul plan. During the last Republican debate, Cain's plan was attacked as regressive, meaning that it would hit the middle-class and poor Americans hardest.

Fifth in a series

Perhaps more than any other Republican running for president this year, Minnesota Rep. Michele Bachmann has railed against taxes. She says they're too high, and that the current tax code should be repealed.

But Bachmann had a somewhat surprising early career: going after tax evaders as a prosecutor for the Internal Revenue Service.

'Know Your Enemy'?

At times, the congresswoman and former state senator has seemed to deny that for nearly her entire professional life, she's been on the public payroll.

Melissa Block speaks with our regular political commentators E.J. Dionne, of the Washington Post and Brookings Institution, and David Brooks, of the New York Times.

Robert Siegel speaks Washington Post reporter Manuel Roig-Franzia about Florida Republican Sen. Marco Rubio's background — and why it is being questioned.

GOP presidential contender Herman Cain, who has made his reputation with his 9-9-9 tax plan, introduced the variant 9-0-9 plan for the poor, who would be exempt from the income portion of the plan. Experts said the poor, who pay little if any federal tax now, would still see a tax hike.

Autofocus cameras hit the stores back in the 1970s, making it dramatically simpler for the average consumer to get a good shot. Later the digital camera made it possible for just about anyone to process their own pictures at home on a computer. Now comes a camera that could represent another kind of photography revolution: the light field camera. Take the picture, but focus it afterwards. Robert Siegel speaks with Lytro founder Ren Ng about the new light field camera that his company is producing.

How do Iraqis feel about the U.S. decision to withdraw all its remaining troops by the end of this year? The issue of a residual American force to train the Iraqi military was hotly debated in Baghdad.

Chicago recently ranked as the city with the second-worst traffic congestion problem in the country, but it doesn't have a lot of money to invest in other transit options. Mayor Rahm Emanuel's solution? A $2 "congestion fee" on weekday parking in public lots and garages downtown.

Other cities have had some success with congestion pricing for parking, but some Chicagoans are skeptical of the plan.