Paul Ryan Pressed For Details On Tax Plan During Debate (VIDEO)

Vice presidential debate moderator Martha Raddatz pressed Republican hopeful Paul Ryan on his ticket’s promise to cut all federal income tax rates 20 percent without increasing the budget deficit or increasing the tax burden on middle-class earners. The Tax Policy Center has said the Republican math doesn't work.

“Let's talk about this 20 percent,” Raddatz said. “You have refused to offer specifics on how you pay for that 20 percent across-the-board tax cut. Do you actually have the specifics or are you still working on it and that's why you won't tell voters?”

Ryan said that his plan would deny loopholes and deductions for millionaires, and that a Romney administration would work with Congress. Raddatz asked, “You guarantee this math will add up?”

“Six studies have verified that this adds up,” Ryan said.

But not all of the six studies are actually studies. As HuffPost has reported, three of them are blog posts or op-eds, and one was paid for by Romney for President Inc.