Yup – all Arizona is asking is that its police enforce what is already American law. I’ve said this before but I’ll try it again: when I was wandering around Europe in 1971-72, I always knew to carry my visa and passport to display to the local police, because they could, and would ask for it on a regular basis. Even today, hotels in Europe ask for your passport. I didn’t consider it an affront to my humanity then, and I don’t see anything wrong with it now. If you’re here as a visitor, carry your ID. If you’re here illegally, tough luck.
(e) Personal possession of registration or receipt card; penalties Every 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.