Arizona: The Anti-Sanctuary State
The state of Arizona wants every city and county in the state to be an anti-sanctuary city. The Senate just passed a bill that would require local law enforcement to enforce immigration law.
The sanctuary city rationale laid out above is solid enough, and it works even if you assume that police forces, systemically and at the level of individual officers, are basically dedicated to the common good. The problem only gets worse when you factor in that these folks the state is now demanding enforce immigration law are not only under-trained and over-worked, but also quite often racist bastards. The latest evidence of this comes from a review (pdf) of Arizona traffic stops, which showed that the cops are 2 to 3 times more likely to search a person of color's car than a white person's. And to add insult to injury, Latinos and American Indians were substantially less likely than whites to have any illegal stuff in their car (blacks were just slightly more likely).