The Republican majority in Congress and the Trump administration are trying to make an example of Boston and its mayor, Michelle Wu, on immigration policy. the Attorney General accused her of actions that are “callous and an insult to law enforcement across America,” and of siding “with public safety threats over law-abiding citizens.” The administration’s “border czar” said he was “coming to Boston” and “bringing hell with me,” and launched personal attacks on the city’s police commissioner.

Why? For years, Boston has had an ordinance that provides:

A law enforcement official shall not detain an individual solely on the basis of a civil immigration detainer request or an ICE administrative warrant after the individual is eligible for release from custody, unless ICE has a criminal warrant, issued by a Judicial Officer, for the individual.

Boston Municipal Code 11-1.9(B).

What does this mean? It means that if a federal immigration official makes a non-mandatory request to keep someone in custody after he is otherwise eligible to be released, the answer will be “no.” It also means that if an immigration officer issues an administrative warrant, which, in the words of the ordinance, “does not confer detention authority on a local jurisdiction,” then the administrative warrant will not be honored. But if a federal judge issues a warrant, then the warrant will be honored.

Does the federal government think that the law requires state or local officials to honor civil immigration detainer requests? Not as far as I can tell. Does it think that the law requires state or local officials to obey administrative warrants not issued by a judge? Not as far as I can tell. So the ordinance doesn’t violate federal law. Indeed, it makes it clear that the City follows enforces federal arrest warrants issued by a judge.

What the federal government is really trying to do is to bully Boston into enforcing federal civil immigration law. This isn’t my area of expertise, and I’m not going to review the Supreme Court’s cases on the topic here, but it seems pretty clear to me that the federal government cannot commandeer the states’ officials and require them to enforce federal law. What Boston is saying to the federal government is, “If you want to enforce federal immigration law in Boston, we won’t stop you. But don’t ask us to do it for you.”

By the way, it’s always been the Republican Party that has cared the most about this constitutional rule against commandeering, in case anyone cares about such things anymore.