The constitutional showdown over sanctuary cities is now one step closer to the U.S. Supreme Court. Late last month, the Justice Department filed a petition asking the Court to hear arguments in United States v. California, a case which asks whether California's status as a "sanctuary state" is illegally hampering federal immigration law. (Sanctuary states are jurisdictions whose officials refuse to participate in the enforcement of federal immigration laws.)
The case centers on the California Values Act of 2017. Among other things, that law forbids state and local police throughout the Golden State from providing certain forms of assistance to federal immigration authorities, such as "detaining an individual on the basis of a [federal immigration] hold request"; "transfer[ring] an individual to immigration authorities unless authorized by a judicial warrant or judicial probable cause determination"; and "providing information" to federal immigration authorities "regarding a person's release date…or other information unless that information is available to the public, or is in response to a notification request from immigration authorities in accordance with" California law.
As far as the Trump administration is concerned, California "openly seeks to undermine federal immigration enforcement" and thus deserves to be slapped down by SCOTUS.
But if the Supreme Court does agree to hear the case, the justices may well take the opposite view. Indeed, if the Court follows a precedent authored by the late Justice Antonin Scalia, the Trump administration is likely to lose.
Printz v. United States (1997) dealt with a provision of the 1993 Brady Handgun Violence Prevention Act requiring local police to assist in the enforcement of federal gun control law. Sheriff Jay Printz of Ravalli County, Montana, challenged the provision on 10th Amendment grounds, arguing that it was unconstitutional for the feds to order state officials like him to carry out a federal statute.
The Supreme Court sided with the sheriff. "The Federal Government may neither issue directives requiring the States to address particular problems," declared Justice Scalia's majority opinion, "nor command the States' officers, or those of their political subdivisions, to administer or enforce a federal regulatory program."
The same logic that applied in Printz would seem to apply equally well in U.S. v. California. If it's unconstitutional for the feds to commandeer the states into enforcing a federal gun control scheme, it's also unconstitutional for the feds the commandeer the states into enforcing federal immigration policy.