For any lawful contact made by a law enforcement official or a law enforcement agency of this state or a county, city, town or other political subdivision of this state where reasonable suspicion exists that the person is an alien who is unlawfully present in the United States, a reasonable attempt shall be made, when practicable, to determine the immigration status of the person.As for the legal side of the thing, first, "lawful contact" may be the most broad language ever written in the history of American legislation. It encompasses almost anything apart from an explicitly illegal traffic stop (which almost doesn't exist anymore: one mph over the speed limit, faulty tail light, "you looked like you were swerving within you lane", you vaguely fit the description of an alleged malfeasor, etc.) or the police barging into your home without a warrant. Basically, lawful contact is not a limitation at all, let alone a reasonable one.
Second, the Constitution’s equal protection clause forbids the government from differentiating between anyone, including illegal immigrants, on the basis of race. Under the Arizona law no one has suggested any other potential grounds for the police to reasonably suspect someone is an illegal immigrant besides the fact that they have Latin American-colored skin. What else could possibly fall under "reasonable suspicion"? I can't think of anything. Governmental racism is, bluntly, unconstitutional.
