A while back, I wrote the story of "Three Identical People", in which I discussed how police could now demand, "Your papers, please," and deport anyone (even a U. S. Citizen) who failed to comply instantly.
It turns out that U. S. Immigration and Customs Enforcement (ICE) has found a new way to deport U. S. Citizens who are members of undesirable races. This one works even if they have their papers.
What happens is this: ICE agents keep you locked in a small room, in this case for 8 hours, applying duress until you finally give in and agree to sign a paper that states you aren't a citizen...even though you have your U. S. birth certificate and ID with you.
It worked so well they've done it a few times since (see this PDF of an ACLU filing, section I. A. 4.) including in this recent case.
Then they send you to Mexico, revoke your passport (if you have one), inform your birth state that your birth certificate is invalid, and so on. Good luck, "becoming a citizen" again.