UPDATE: The opinion is here.

The opinion is by Justice Scalia affirming, requiring Arizona to accept the federal form for voter registration (under Congress’s Elections Clause powers). Justices Thomas and Alito dissented.  [No Shelby County opinon today.]

Here was my original post on the case, “Sleeper Case of the Year?”, where I wrote: “This is one of those cases where if the Supreme Court affirms the result in this case (that Arizona must accept the federal form), it will be no big deal, but if the Court reverses it would mark a major change in U.S. election law.”

More to come when the opinion posts.