Why is SB1070 unconstitutional?

Someone asked me to explain why SB1070 is unconstitutional. I believe there are several reasons, but in the interest of keeping it short, let me address the most straightforward one.

Let's establish the facts. First, no one can tell with certainty whether a person is a citizen or not. Not even Governor Brewer. Second, American citizens are not required to carry any documentation that proves their citizenship. I am aware that there are lots of people who are volunteering to carry their drivers license, US passport, and birth certificate in the pocket of their swimming shorts, but that doesn't change the fact that no law exists that obliges anyone to do so.

The 14th Amendment of the US Constitution reads, in part:

"No State shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States; nor shall any State deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws."

So let's say a police officer stops me on the street, on suspicion of being an illegal alien (SB1070 says he can). I tell him that I'm a US citizen, and that he has no authority to detain me. He thinks I'm lying, so he arrests me "to establish my immigration status" (again, being in full compliance of the new law).

By depriving an American citizen of his liberty, without due process of law, the police officer is in violation of the Constitution.

Q.E.D.

Vitaliy