But seriously... In the bill (Thanks Cupcake!!! Now we can actually have a rational discussion) it states that the cops must first have pulled someone over for something else and only then check their immigration status. And the Supreme Court has already established that pulling someone over for racial profiling is not considered to be "reasonable suspicion". Unlike what our president said, it is illegal for a cop to harass a father and his son just going out for an ice-cream just because they are Hispanic and don't have their "papers". And all the worry about "papers" is also fairly ridiculous... The "papers" are forms of documents that all citizens probably have available anyways (a valid Arizona driver's license works!), esp. if they are driving and get pulled over. I never think twice when a cop pulls me over for speeding and asks for license, registration, and proof of insurance. And as the cop is checking if there are outstanding warrants on me, in Arizona they'd just use the computer to check immigration status as well (which you could consider as another form of warrant checking, since being in this country illegally is, well, illegal).
Could there be racist cops that will want to pull Hispanics over just because of their race? Yes, but then they are abusing some different law in violation of the person's civil rights. It isn't this new law that is causing the cop to pull them over... All it is doing is saying that the state needs to be in compliance with Federal immigration laws and dictating how this is to be done.
I hope my state will enact similar legislation, esp. since we're also a border state albeit a border with Canada instead of Mexico. And actually, states that don't already have something similar (even if not explicitly stated) are in violation of the US Constitution's Supremacy Clause (Article VI Clause 2): "This Constitution, and the Laws of the United States which shall be made in Pursuance thereof; and all Treaties made, or which shall be made, under the Authority of the United States, shall be the supreme Law of the Land; and the Judges in every State shall be bound thereby, any Thing in the Constitution or Laws of any State to the Contrary notwithstanding." In other words, the supreme law of the land is the Federal immigration law, which the Arizona law keeps stating as its reason for having the law and the need to implement such a law to begin with, and any state that does not try to enforce the Federal immigration law (like they'd do for the Federal kidnapping law, etc.) would be going against the constitution.