Palin: 'Chains' comment should be 'nail in the coffin' for Biden

"They’ve said it. Every Republican’s voted for it. Look at what they value and look at their budget and what they’re proposing. Romney wants to let the — he said in the first 100 days, he’s going to let the big banks once again write their own rules — unchain Wall Street," Biden said. "They’re going to put y’all back in chains. He’s said he’s going to do nothing about stopping the practice of outsourcing."

Mitt Romney has blasted the comments, saying Wednesday in an interview with CBS they were "designed to bring a sense of enmity and jealousy and anger" to the presidential race.

The Obama campaign has hit back, calling Romney's attacks "unhinged" at a time he was running tens of millions of dollars' worth of attack ads. But Palin looked to turn that retort back on Team Obama.

“And Joe Biden isn’t unhinged today?” Palin said.

Earlier Tuesday, during an interview with CNBC, former New York City Mayor Rudy Giuliani suggested that Biden was not fit for the office of vice president.

“I think the vice president of the United States has become a laugh line on late-night television. I mean, I’ve never seen a vice president that has made as many mistakes, said as many stupid things," Giuliani said. "There’s a real fear if, God forbid, he ever had to be entrusted with the presidency, whether he really has the mental capacity to handle it.”

The Romney surrogate went on to say the vice president "just isn't bright."

"He’s never been bright. He isn’t bright. People think, 'Well, he just talks a little too much.' Actually, he’s just not very smart," Giuliani said.