Romney and Giuliani tussled over immigration at the beginning of the debate.
WASHINGTON (CNN) - In the first moments of the CNN/YouTube debate, sparks flew between former New York City Mayor Rudy Giuliani and former Massachusetts Gov. Mitt Romney on the issue of so-called sanctuary cities for illegal immigrants.
After Romney attacked Giuliani for saying New York was not a sanctuary city, Giuliani responded by saying Romney lived in a "sanctuary mansion" and that Romney employed illegal immigrants at his own home.
Romney denied the allegations.
- CNN Political Assignment Editor Katy Byron