Anyway, I found a really good piece on the whole issue over at PJM.
As I understand the opposition to the recent Arizona law, it boils down to something like the following: the federal government’s past decision not to enforce its own law should always trump the state’s right to honor it. That raises interesting questions: Does the state contravene federal authority by exercising it? If the federal government does not protect the borders of a state, does the state have a right to do it itself?
Read the whole thing. This isn't about race.
ETA: What a headline: Illegal immigrants plan to leave over Ariz. law
Of course, not so great news for those of us in neighboring states.