Officially, it’s the United States-Mexico-Canada Agreement, but it’ll go down as NAFTA 2.0 — President Donald J. Trump’s NAFTA 2.0, and a vindication of an approach his critics claimed would lead to disaster.

Mexico got on board weeks ago; Washington and Toronto agreed over the weekend. Canadian Prime Minister Justin Trudeau, who sparred for months with Trump, tweeted: “a good day for Canada & our closest trading partners.”

Jesus Seade, the negotiator for lefty Mexican President-elect Andres Manuel Lopez Obrador, said, “NAFTA 2 will give certainty and stability to trade.”

Yes, negotiations got rough along the way, but that was inevitable once Trump refused to accept the establishment don’t-rock-the-boat pieties.

Among the biggest changes: US dairy farmers get wider access to Canada’s dairy market; intellectual property gets tighter across-the-board protection and more of the autos sold in North America will be made in North America.

With US-European trade tensions also easing, the board is clear for facing down China. Even trade-war doves agree that Beijing doesn’t play fair — but three presidents over 24 years did nothing to make it behave.

China is on unmistakable notice that Trump is different, and it’s already found that tit-for-tat tariffs get it nowhere.

We’ll admit that the president’s approach left us nervous, but it’s hard to argue with the result: Trump has once again delivered on a campaign promise that his rivals called a fantasy.

A politician who does what he says he’ll do: Imagine that.