Cooperate or else
Cooperate or else (NICHOLAS KAMM/AFP/Getty Images)

Your undocumented immigrants or your federal funds: That is the appallingly brute threat to New York and other so-called sanctuary cities made in an executive order Wednesday from President Trump that purports to keep America safe from terrorists and predatory aliens — while actually threatening to do the opposite.

Trump decreed that states and cities that refuse to help federal immigration authorities apprehend undocumented immigrants will be denied federal grant funds.

What the order means in practice is yet to be seen, but conceivably on the line is $7 billion New York City expects to receive from Washington in the coming year for everything from schools to homeless shelters to domestic violence programs to swimming pools. More likely at stake are as much as $160 million in anti-terrorism and crime-fighting funds, tenuously related as they are to the Trump order’s stated public-safety purpose.

But the law’s not on Mr. Law-and-Order’s side: The feds have minimal power under the 10th Amendment and Supreme Court precedent to…