SB 1070 falls.

No one covering the latest Supreme court ruling seems to be noticing this crucial point:

(2) It is not clear at this stage and on this record that §2(B), in practice, will require state officers to  delay the release of detainees for no reason other than to verify their immigration status.  This would raise constitutional concerns.   And it would disrupt the federal framework to put state officers in the position of holding aliens in custody for possible unlawful presence without federal direction and supervision.  But §2(B) could be read to avoid these concerns.  If the law only requires state officers to conduct a status check during the course of an authorized, lawful detention or after a detainee has been released, the provision would likely survive preemption—at least absent some showing that it has other consequences that are adverse to federal law and its objectives.  Without the benefit of a definitive interpretation from the state courts, it would be inappropriate to assume §2(B) will be construed in a way that conflicts with federal law.  Cf.  Fox v.  Washington, 236 U. S. 273, 277.  This opinion does not  foreclose other preemption and constitutional challenges to the law as interpreted and applied after it goes into effect.  Pp. 22–24.

In other words 2(B) stands if and only if in actual practice it is not allowed to be the basis to detain anyone.