New Jersey Gov. Chris Christie stirred up a fuss last week when he urged New Yorkers to move across the river because our taxes are headed upward.

The governor's "latest political stunt" doesn't deserve a serious response, groused an aide to Mayor-elect Bill de Blasio, who campaigned on a pledge to raise city income taxes on earners making $500,000-plus a year.

Actually, New Yorkers should thank Christie profusely for handing the city's administration-in-waiting a tough, commonsense warning.

While Christie didn't mention de Blasio by name, he did make it clear that a smart leader doesn't go out of his way to anger the people who are springing for the greatest share of the public tab.

"While I feel badly for New Yorkers," the governor said, "come to New Jersey!"

De Blasio shouldn't be complacent about that. If higher taxes for the wealthy can make for a wonderful campaign slogan, it proves to be a limited mantra for governing.

New York City's richest 1 percent account for more than 43 percent of our total income-tax revenue, says the city's Independent Budget Office.

And this 1 percent also happens to be highly mobile. It can live in Greenwich, Conn., Nassau County, the Hamptons or the suburbs of New Jersey or anywhere else.

Vilifying this group is wrong.

De Blasio says he would use a tax hike on high-earners to fund a universal prekindergarten program in the city -- which is a worthy goal. But almost everyone likes the idea of universal pre-K, and there may be money in Albany to pay for it without raising taxes.

De Blasio says he still will ask for the tax increase, which requires Albany's permission. Perhaps he just wants to remain consistent. But a less charitable view is that this is a wedge issue that works for him, or it's a revenue source for new union contracts. He likes to point out that he has stood before wealthy New Yorkers and told them he'd raise their taxes. All right, but the campaign's over.