SB1070) and reform has opened up a controversial rhetoric in the United States. In fact, it's one of the few times in the history of the country where the Federal government has sued a state government. The Feds claim that they have the sole responsibility to enforce immigration laws.
The Arizona laws mirrors the Federal law, and makes it illegal for someone to be present in the state without immigration paperwork. It's not a civil level of illegality - it's a criminal level that makes it possible for the state to actually deport someone.
Opponents of the law - the Federal Government included- state that the law opens up the possibility for racial profiling, which is something that Civil Rights leaders and activists are trying to avoid.
However, the state of Arizona and those who are for the law point out that law enforcement cannot demand immigration status proof unless someone is involved in another legal problem, crime, or has been pulled over.
If Arizona is successful in defeating the Fed's lawsuit, there are already other states lined up to make similar laws. Many natural born Americans and also legal immigrants are for the bill, as illegal immigrants have become a problem in some Southwestern States. Drug crimes, abuse of the social system, and driving wages down are all things that many cite as reasons why there should be a crackdown on illegal immigration.
The Arizona immigration law could be dubbed unconstitutional - then again, comprehensive reform may be coming down the pipelines.