I think the debate is poisoned by the partisan nature of politics, especially in the current times.
The GOP power base has declared that there's really no room for tolerance on immigration issues. McCain, Bush 43 etc... were all hammered by their own party for taking a pragmatic position.
This has let the nut jobs mingle with the Republicans. I do think many pushing the AZ law were motivated by racism and a sense of stopping a Hispanic invasion.
That's not to say that there are reasonable AZ folks who support the law. Certainly there's a sense of outrage and that the Federal government isn't doing enough to stop the problem, and this is a National issue.
Obama's general policy position doesn't seem to be all that far from Bush. And recent reports seem to indicate he's been even more aggressive in cracking down on illegals.
Under Obama, More Illegal Immigrants Sent Home : NPR
I'd think people should be giving Obama credit for his success during these trying times.
-spence