But, although by LAW he had zero authority to do anything about those cities, he vetoed a plan to allow in-state tuition for illegal aliens, opposed granting illegals drivers licenses, and encouraged state troopers to enforce immigration laws. All this while Rudy defended, encouraged and welcomed illegal immigration into New York City.
http://777denny.wordpress.com/2007/08/21/giuliani-defends-romney-condems-sanctuary-city-policies/
And whether you choose to believe his commitment to follow through or not, his positions and his record on this issue are exceedingly better than that of any of the other viables -- Huck, McCain and Rudy (or any of the dems).
Mitt got good marks for how he actually governed, as regards illegal immigration:
Assessment of Past Immigration Actions in Political Office
Based on Congressional, Gubernatorial and Mayoral actions
Rudy bad
Huck bad
McCain abysmal
Fred fair
Mitt good
Paul good
Tancredo excellent
Hunter excellent
Republican Presidential Candidates On Immigration Issues
http://www.betterimmigration.com/candidates/2006/prez08_gop1.html