CBS News' Ryan Corsaro reports:

Who writes your material?

That’s what Rudy Giuliani wants to know about Senator Joe Biden, who got a laugh at last night’s debate by saying that the mayor’s entire message is “a noun, a verb and 9/11.”

“I think somebody wrote it for him," Giuliani said. "I want to know who wrote it for him.”

He added, “I’m running on my record. Joe doesn’t have a record like that to run on.”

While campaigning in Orangeburg, NY, the mayor also jumped on Hillary Clinton for her comments on driver's licenses for illegal immigrants in New York.

"Last night was the first night I saw her take two positions in front of the same audience in one minute, in front of the same audience," Giuliani said. "Now that’s extraordinary. That I have never seen before."

"If you can't take a position on something like drivers licenses," he continued, "what are you going to do about Ahmadinejad?"

The mayor himself accidentally flubbed while speaking to the press, first referring to Clinton's stance on “license plates” instead of driver’s licenses, though later used the correct words.

Can you imagine what Giuliani might say if Clinton wanted to allow illegal immigrants to have vanity plates?