Whether it’s diplomats or professors, people following Trump’s global moves are starting to lose it.

President Donald Trump may be backing down on his threat to seize Greenland, but his push for the island has already changed the way foreign policy is done in Washington and beyond.

More than any other global issue I’ve seen Trump tackle, his obsession with Greenland has shifted paradigms and broken brains. And I’m talking about big brains: diplomats, foreign policy analysts, economic specialists. People on the left and a fair number on the right.

Even diplomats not from Europe are rattled.

“It was like, huh?” said an African official in Washington. “The shocking part was the level of the threat, how serious he was. And it’s not over.”

Suzanne Maloney, a Middle East analyst who directs the Brookings Institution’s foreign policy program, said it has felt “as though the world has gone mad.” She added: “The language, the determination on this particular issue just feels disconnected from our national interest.”

Not long ago, many foreign policy professionals were still asking if the post-World War II “rules-based international order” was dead. In the wake of Trump’s Greenland gambit, I’m hearing more flat-out declare it’s a corpse. Canada’s leader, Mark Carney, said as much at the World Economic Forum this week.

That means foreign policy consultants are rethinking advice they give to clients, while think tankers are reconsidering their travel and study plans. Maloney, for one, said she had to submit her department’s policy research priorities for the coming fiscal year to her superiors this week, but that she warned them the list could change by next week.

Diplomats from Europe said the Greenland crisis has created a new reality because it’s clearer than ever that even allies are not safe from Trump’s machinations.

“It creates a sort of fear in the European Union,” one European diplomat told me. “It’s not just about expanding our imagination, but just to realize this is a different day and the traditional ways — the rules, the laws — don’t necessarily apply. Everything is now negotiable.” (I granted the diplomat and others I spoke to anonymity to discuss a sensitive issue.)

That’s even though Trump toned down his rhetoric Wednesday. He first said he won’t use military force to take over Greenland and later announced he’d withdraw a threat of tariffs after reaching a “framework” deal over the territory. Few details were immediately available.

But Trump, who has wanted Greenland since his first term, changes his mind so often that Europeans — or any other global actor — would be foolish to trust that this issue is resolved. He has a history of walking away from deals, including ones his administration crafted. He also has three more years in this term.

The sense from Trump critics I spoke to for this column was that they’re not ready to relax even though he’s softened his tone.

“His overriding interest is to expand the map of the United States,” said Eric Green, a former senior National Security Council official who dealt with Russia and Central Asia in the Biden administration. “Sooner or later he’s going to come back to that.”

Trump’s Greenland desires have scrambled the plans of many foreign affairs practitioners to a degree that’s unusual even for a president who delights in upending conventional wisdom.

The whole Greenland debacle is especially hard for people who teach international relations, many of whom keep having to redo their syllabi. These scholars are trained to use neutral language to explain the actions of power players. The goal is to help students learn methods to understand the world.

But “there comes a point where you just want to say this is a fucking stupid idea,” said Daniel Drezner, academic dean at Tufts University’s Fletcher School…