All those who are so staunchly opposed to the Arizona Bill making it against the law for an alien not to have an Alien Registration card in their possession obviously have no clue that it simply mirrors a Federal law which is already on the books.

Sec. 264. [8 U.S.C. 1304]

(e) 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). 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.

http://www.uscis.gov/ilink/docView/SLB/ ... -8289.html