Rudy has run the nation's largest city

During the Oct. 30 Democratic debate, Sen. Joe Biden won the biggest laugh of the night when he said "there's only three things that (Rudy Giuliani) mentions in his sentences — a noun, a verb and 9/11."

But the first part of this passage had this doozy: "And the irony is Rudy Giuliani, probably the most underqualified man since George Bush to seek the presidency, is here talking about any of the people here."

When the audience laughed, Biden clarified by saying, "I mean this sincerely; he is genuinely not qualified to be president."

We talked to historians to assess Biden's statement and see how Giuliani stacks up. (Our detailed look at the candidates' experience can be found in our story here.)

Historians like Sean Wilentz, a Princeton history professor who is sharply criticial of George W. Bush, said you can't discount Giuliani's eight years as mayor of New York City.

"Experience on the local level doesn't carry much weight in presidential campaigns," Wilentz said. "But it's the city of New York. It's no ordinary city, and that's an advantage he has."

Add a crisis like 9/11, where Giuliani was involved in the ground zero rescue effort, and he has experience other candidates don't have, said Stanley Renshon, a political science professor for the City University of New York.

"Giuliani got a taste of what it was like to be president," Renshon said. "He was the only person at the epicenter of an attack on American soil."

He also has six years as U.S. attorney in New York, where he prosecuted mob figures and Wall Street titans.

By contrast, Biden's fellow Democrat John Edwards has only six years of experience in the Senate. Barack Obama has only three in the U.S. Senate and eight in the Illinois Senate. We find Biden's rhetoric is not backed up by the facts because it ignores Giuliani's considerable experience as U.S. attorney and mayor of the nation's largest city. That's not just wrong, that's Pants on Fire wrong.