In response to the persistent and substantial questions about the math of his tax plan not adding up, Mitt Romney and his campaign frequently argue that six independent studies back him up by ratifying the arithmetic of the centerpiece of his domestic agenda.

But the talking point about the talking point is unraveling.

More and more mainstream from outlets are pointing out that they fail to validate its soundness. And on Sunday Romney senior adviser Ed Gillespie was challenged on Fox News by Chris Wallace, who questioned whether the studies are really nonpartisan.

“Those are very questionable. Some of them are blogs. Some of them are from the AEI [American Enterprise Institute], which is hardly an independent group,” Wallace said. “One of them is from a guy who is — a blog from a guy who was a top adviser to George W. Bush. These are hardly nonpartisan studies.”

“These are very credible sources,” Gillespie said.

Of the six studies, two are blog posts by the conservative American Enterprise Institute; one is a report by the Republican-friendly Heritage Foundation; one is a paper by Princeton professor and former George W. Bush adviser Harvey Rosen; the fifth and sixth are a paper and Wall Street Journal op-ed by Harvard economist Martin Feldstein, an adviser to the Romney campaign.

In addition, not all the studies appear to reach the same conclusion as Romney. He contends they show that it’s possible to lower tax rates across the board by 20 percent and avoid adding to the deficit by unwinding deductions and credits for high incomes. That’s not the case.

more: http://tpmdc.talkingpointsmemo.com/2012/10/romney-challenged-on-six-studies-validating-tax-plan.php?ref=fpa