JOHN C. CALHOUN SMILES:

On the same day last week that Donald Trump nominated noted immigration hawk Sen. Jeff Sessions for Attorney General, New York City declared that it would stick to its “sanctuary city” policy—setting up a battle that will likely occupy a lot of national attention during the next Administration. . . .

This is a political fight both sides will relish taking on. Trump got a big boost early in his campaign by shining a spotlight on the murder of Kate Steinle by an illegal immigrant in San Francisco. The murderer had previously been detained by the San Francisco police, but under SF’s sanctuary city policy—which is more militant than New York’s—the city refused to honor a request from the federal government to transfer him, and instead released him. This was a story to which Trump returned throughout his campaign.

Furthermore, as I wrote on Friday, the nomination of Sen. Sessions as AG likely signals that the Trump Administration will seek first and foremost to fulfill his campaign promise of a more hawkish line on immigration through the enforcement of existing laws against criminal illegal aliens. Unlike previous Attorneys General, Sessions will presumably not hesitate to use the full range of remedies, including financial and legal sanctions, available to the federal government to compel cooperation from reluctant municipalities. And it helps Trump’s populist brand to pick fights with New York City liberals who want to protect illegal immigrants in disregard of the law.

For their part, de Blasio and other leaders of deep-blue cities also have strong incentives not to back down. Again, this will partly be a matter of politics: fighting Trump plays as well with de Blasio’s constituents in NYC as fighting de Blasio does with Trump’s backers in the heartlands. But there are other considerations. Right now the NYC policy is not to call the feds about a suspect’s immigration status until the the person is convicted, while federal policy technically requires the local cops to call the feds as soon as they find out someone is here illegally. Cities with large illegal immigrant policies, like New York, feel that such a policy will deter its residents from cooperating with the police or calling emergency services.

Such a fight will galvanize public opinion on each side. The Jacksonians will see only flagrant disregard for law and order; for historical reasons, many in the south will also be angered by what they’ll perceive as deeply hypocritical flouting of federal authority. . . .

But the law will not be on de Blasio’s side. And it is a deep principle of American history that the state and local authorities not be allowed to override or nullify federal law. This is a point that liberals reaffirmed with particular vehemence on the immigration front as recently as a few years ago, when arguing (successfully) that Arizona’s immigration laws were preempted by federal policy.

As we’ve been writing around here, Donald Trump is the most purely Jacksonian character to win the White House since possibly Andrew Jackson himself. And now he may have a nullification crisis on his hands. I can’t imagine Bill de Blasio ever dreamed he would wind up as the heir to John C. Calhoun—but he just might.

Technically, states’ refusal to cooperate with a federal regulatory scheme isn’t the same as nullification, and it’s not even illegal unless it violates a condition on federal funding. But these niceties aren’t likely to get much attention.