(CBS News) WASHINGTON - Former New York City Mayor Rudy Giuliani had harsh words for Vice President Joe Biden's "chains" comment, questioning his "mental capacity" to be president.
"That was an absolutely blatant appeal to racism," Giuliani said Sunday on "Face the Nation." "I would consider [his statement] to be an absolutely disgusting appeal to racial sentiment."
Giuliani was referring to comments Biden made at a campaign rally in Virginia last Tuesday when he said Romney's "going to let the big banks once again write their own rules - unchain Wall Street!" adding, "They're going to put you all back in chains."
The Romney supporter said he wonders if Biden "has the kind of balance to be president."
"This guy is like one gaffe after another, and he's a joke on late night television. I think they've also locked him in his room for the rest of the campaign," Giuliani said. "How about the vice president of the United States apologize for at least what appears to be some kind of vicious pandering. I would accept that."
Sen. Richard Durbin, D-Ill., defended the vice president, saying, "There isn't a racist bone in Joe Biden's body and to suggest that, I think, is over the edge. The fact is Joe Biden throughout his career has fought for equality and opportunity and to suggest something else, it may have been a misuse of words, but to take it to that extreme is just too much, Mr. Mayor."
"I'm not going too far; Joe Biden is going to far," Giuliani quipped back.
Durbin, however, reminded Giuliani that he backed Sarah Palin as vice president in 2008. "You told America at the Republican convention that Sarah Palin should be the vice president of the United States, that she was ready to be commander in chief and president. That speaks for itself," Durbin said.
"I think Sarah Palin actually is operating at a level quite a bit above Joe Biden," Giuliani responded.
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On the issue of Mitt Romney's tax returns, Durbin defended Senate Majority Leader Harry Reid's accusation that Romney did not pay taxes some years. Durbin used Romney's words against him, saying, "It's time for Mitt Romney to put up or shut up," which is what Romney said about Reid for refusing to name his source.
"We know he's the first presidential candidate in history to run for office with a Swiss bank account and has disclosed the tax shelters in the Cayman Islands and Bermuda," Durbin added.
Giuliani said, "There's nothing wrong with Governor Romney's taxes," adding that he is "sure" Romney has been audited "up, down, backwards and forward."
The Romneys "laid out a year of taxes and will lay out another year of taxes. It's precisely what John McCain did and John Kerry did," ," Giuliani said. "Nobody raised the issue."