Scalia's dissent is spot on. Since AZ literally "copied" Fed. law,... and the Fed's won't enforce a law long on the books, this is a chipping away of the 10th Amend. regarding states rights.
The law the Fed won't enforce, AZ passed an identical copy through state legislature, and the SCOTUS shot down 3 of 4 provisions.
Title 8 Sec. 1304e
(e)
Personal possession of registration or receipt card; penaltiesEvery alien, eighteen years of age and over, shall at all times carry with him and have in his personal possession any certificate of alien registration or alien registration receipt card issued to him pursuant to subsection (d) of this section. Any alien who fails to comply with the provisions of this subsection shall be guilty of a misdemeanor and shall upon conviction for each offense be fined not to exceed $100 or be imprisoned not more than thirty days, or both. [/color]
http://www.law.cornell.edu/uscode/text/8/1304The sovereign rights of states to protect their borders has been chipped away.....Little by little....
Questioning Roberts motives on this.