SUMMARY: At the CNN/YouTube debate, the candidates argued about immigration, crime and Iraq. We found they generally got their facts right, although Huckabee distorted the facts on an education program for immigrants and Romney missed an easy one about the Red Sox.

From the moment a CNN technician clicked "play" on the first YouTube video, Mitt Romney and Rudy Giuliani launched into a furious game of immigration one-upsmanship.

Romney accused Giuliani of being too welcoming to illegal immigrants and running a "sanctuary city." Giuliani fired back that Romney had run a "sanctuary mansion" because illegal immigrants worked on his lawn.

The back-and-forth in the St. Petersburg CNN/YouTube debate was a reminder that immigration is a key issue for Republican voters, especially the ones who are most likely to go to the polls in the primary elections in January.

Much of the St. Pete debate focused on policies in New York and other cities that direct municipal employees not to ask people about their immigration status. Critics call these "sanctuary cities" and say they provide too much protection for illegal immigrants. Supporters say the cities are merely trying to make sure that immigrants are not afraid to report crimes or communicable diseases. (For our full report on the sanctuary city debate, click here.)

Our findings from the debate:

* Huckabee gave a misleading account of a proposal to provide in-state tuition for children of illegal immigrants. We gave him a Barely True.

* We scored Romney with an error for missing an easy one about his beloved Red Sox.

* Ron Paul had his numbers right when he claimed the most campaign contributions from people in the military.

* McCain correctly said he saved taxpayers billions on a "bogus Air Force Boeing tanker deal where people went to jail."

* Giuliani accused Romney of employing illegal immigrants at his home, which Romney denied. But Romney's denial contradicts a well-documented investigative story, so we found his claim Barely True.

* Giuliani also accused Romney of failing to challenge Massachusetts cities that didn't turn in illegal immigrants, a claim we found Mostly True.

* Romney accused Giuliani of being welcoming to illegal immigrants based on a 1994 statement by the New York mayor. We found that to be True.

* Finally, Romney made the dramatic assertion that 68 percent of births to black women are out-of-wedlock births. Centers for Disease Control statistics back him up, so we found this item True.