Sanctuary Cities and Federalism

Sanctuary Cities have become a brisk topic in the wake of last week’s San Francisco shooting.  A “sanctuary city” is one that has used its local legislative power to instruct local law enforcement not to cooperate with federal immigration officials.  The point, of course, is to protect unlawful entrants to the U.S. from deportation, at least with respect to those aliens who have committed serious crimes.  In San Francisco, the sheriff ignored an ICE detainer request for Francisco Sanchez, the alleged shooter.  The detainer request asked only that the SF sheriff notify ICE of his imminent release and detain him until ICE could take him into custody.  
    Whatever you may think about the wisdom of sanctuary cities, the purpose of this post is to explore the ways in which sanctuary cities could constitutionally be compelled to respond to detainer requests.  First, but most cumbersome, would be state legislation mandating local authorities to respond and comply with detainer requests.  Of course, there are many states that are unlikely to do this and, even where the state political will might be present, there could be obstacles under state law.  Some states provide a considerable degree of legislative independence to certain municipalities. As I am no expert on this aspect of municipal law I only note the possibility.
    Second, Congress could change the law to make state and local compliance with unlawful detainer requests mandatory, if such a change could be enacted over a likely presidential veto.  But even enacted into law, opponents would object that this mandate violates the rule of Printz v. United States, which holds that states and localities may not be compelled to enforce or administer federal law.  Left open after Printz are such questions as whether states may be compelled to supply arrest statistics and the like.  So, would compulsion to honor detainer requests be more like the forced background checks at issue in Printz or arrest statistics?  On one hand, a telephone call to ICE to notify of an upcoming release of a person subject to a detainer request is less burdensome that compiling and supplying arrest statistics, nor does this involve enforcement of federal law.  ICE will take care of that.  On the other hand, mandatory compliance with detainer requests can be seen as a modest enforcement of federal law.
    Third, if Printz bars mandatory detainer compliance, Congress could condition local and state receipt of fedearl funds in aid of law enforcement on compliance, so long as the financial pressure is adequate but not coercive.  Politically, this is unlikely to happen. Thoughts?

Comments

[confused by your post]

I know little about criminal law but I'll ask related question here. Every single day local law enforcement officials release those they've detained/jailed in connection with enforcing state law. Do local law enforcement officials routinely notify federal law enforcement officials if they believe the detainees have violated federal criminal laws? Do they routinely agree to detain such suspects until the feds can pick them up?

[Calvin Massey]

Confused,
If there ia a federal warrant for their arrest state and local officials comply with the warrant. The issue in sanctuary cities arises because ICE detainer requests are just that, requests. The reason for the request is that the person in state custody is also wanted for immigration violations and subject to deportation. Sanctuary cities dislike deportation of unlawful entrants to the US (at least when they are only petty criminals) and so refuse to comply. Should they be made to comply? If so, what is the mechanism for doing so?

[anon]

Why not issue a warrant for felony violation of immigration law? Isn't a felony to reenter after the first deportation?