Arizona Gov. Brewer dealt with the immigration bill very neatly this afternoon — she signed the bill, supporting it unapologetically, but at the same time issued an executive order directing the development of a training program on how to implement the law without racial profiling. The lefties outraged by the bill aren't going to be placated by the executive order (which is kind of redundant, since cops everywhere are awash in sensitivity training), but it will be helpful for lots of Arizonans who support the bill but don't want to feel guilty about it.
Be all that as it may, I think the biggest impact of the new law won't actually be in its implementation; rather, the hyperbolic fear-mongering by the bill's opponents will actually amplify its effect far beyond anything the sponsors could have wished for. The bill on its own obviously isn't going to create a police state or Nazi Germany, but it's also not a magic wand that's going to make illegal immigration go away — it's a modest measure part of which simply parallels federal law, and gives police some extra useful tools (citizens, too, who may now sue sanctuary jurisdictions). But if the thing had been passed and signed with little fuss, it wouldn't have half the attrition effect it's going to have.
So my advice to the open-borders folks: Fear-monger away!