Is our country headed for a new nullification crisis? Are our cities and states gearing up to defy the federal laws that, together with our Constitution and treaties, make up the “supreme law of the land”?

It certainly looks that way, based on the confrontation brewing over so-called sanctuary cities. These are cities and other locales that have adopted policies against cooperating with the enforcement of our immigration laws.

President Trump announced on Wednesday plans to redeem his campaign pledges on immigration. At the Homeland Security Department, he signed orders to start the “barrier” on the Mexican border and to withhold federal funding to cities pledging to defy the law.

Watch out, New York, where Attorney General Eric Schneiderman has been cruising for a bruising. The day before Trump was sworn in, the left-wing lawman circulated to cities guidance on how to dodge federal immigration enforcement.

“Public safety relies on trust between law enforcement and the communities they serve,” Mr. Schneiderman said. “No local law enforcement agency should have to undercut that trust just to carry out Donald Trump’s draconian immigration policies.”

Mr. Schneiderman provided a whole rigmarole on how cities in our state don’t have to pitch in to help enforce these laws, except in the narrowest circumstances. What a cynical maneuver against our democracy — and in the middle of a war.

Nor is Mr. Schneiderman alone. It turns out that left-wing politicians across the land are maneuvering for a confrontation with the federal government over the tough new line on illegal immigration the voters asked for in November.

The 2016 Republican platform stated flatly that “‘sanctuary cities’ violate federal law and endanger their own citizens” and “should not be eligible for federal funding.” Yet the votes had barely been counted when sanctuary cities began fighting back.

Mayor Rahm Emanuel of the village of Chicago fetched up at Trump Tower in early December. He presented the then-president-elect with a petition on behalf of sanctuary cities, signed by, among others, Mayor de Blasio.

Mr. de Blasio, meantime, is being sued by two members of the state Assembly for his plan to destroy certain records from the city’s ID card program. Hizzoner wants to protect undocumented immigrants from America’s government.

New York’s drama is part of a movement that, some reports suggest, now involves more than 300 jurisdictions. Which is what raises the question of whether we are going to end up in a new nullification crisis.

The original crisis erupted in the 1830s, when South Carolina tried to defy a federal tariff act. Vice President John Calhoun quit to run for Senate, the better to defend the Palmetto State. President Andrew Jackson prepared for war, before a compromise was reached.

It wasn’t the only nullification. Virginia and Kentucky once blocked enforcement of the Alien and Sedition Acts, passed in 1798 during the Quasi War with the French. Some states — heroically, in my view — refused to enforce the Fugitive Slave Act.

What is going to bring the current crisis to a head is hard to predict. The governor of Texas, Greg Abbott, has just warned the Travis County sheriff that her jail could become the first to lose taxpayer funds unless she reverses her plan to make Austin a “sanctuary.”

Mr. de Blasio has been fighting in court over his plan to destroy records to keep them from being used against illegal — or otherwise undocumented — immigrants. And my guess is that many, even most, New Yorkers get it.

Our city is the world’s premier metropolis precisely because of its immigration and diversity. If Mr. Trump delivers the growth he’s promised, America will need all the help it can get and will be begging immigrants to stay.

I like the way all this is put by Ravi Batra, the lawyer for the Assembly members suing Mr. de Blasio. He is as full of enthusiasm for immigration as any New Yorker. But he sees a public-safety issue and also gets the supremacy clause of the Constitution.

That clause says the Constitution, federal laws and treaties “shall be the supreme Law of the Land” and “the Judges in every State shall be bound thereby,” local laws to the contrary notwithstanding. So he’s a Democrat in court against the city.

“Before I’m a Democrat, I’m an American,” he explains.

This column first appeared in the New York Post.