Arizona should. The federal government is not doing their job as outlined in the contract known as the Constitution. The federal government is incompetent. It is woefully and willfully not doing their job and now want to sue Arizona because Arizona passed a law that would do that which the federal government should do.
If I were Arizona I'd sue the federal government for breach of contract as well as the cost of the defense of the Arizona law passed that states that which the federal law has already stated.
Quit the crap and protect the border. Obama, you can get votes some other way. They're getting thinner, but there are still a lot of unmined graveyards in the Chicago area. Calumet alone should give the advantage in votes. If not, there are all those empty lots in Detroit that they plan to garden. Think counting crows.