Analysis: Trump just left open using military force against a NATO ally

President-elect Donald Trump is the king of not ruling things out. It’s his default response when a possibility, no matter how far-fetched, gets floated, both because he has little regard for norms and because he seems to view extreme ideas as negotiating ploys.

So the fact that the incoming president just declined to rule out using the U.S. military to take Greenland and the Panama Canal shouldn’t be too surprising, nor should we regard it as any real indicator of Trump’s intentions.

But this lack of a clear “no” is quite different; he just left open using a military threat against a NATO ally, Greenland. And NATO rules require an attack on any member to be treated as an attack on them all.

That’s certainly no small thing, even if it’s just Trump being Trump.

Trump was asked at a news conference Tuesday whether he would rule out using “military or economic coercion” to take Greenland and the Panama Canal, both of which he has suggested he would like to claim for the United States. And his response, twice, was that he wouldn’t rule it out.

“No,” Trump initially said, adding: “I can’t assure you on either of those two.”

When pressed again, Trump doubled down.

“I’m not going to commit to that,” he said. “It might be that you’ll have to do something.”

The exchange is the latest ratcheting up of Trump’s increasingly imperialistic entreaties. In addition to Greenland and the Panama Canal, Trump has spoken/joked about turning Canada into the 51st state and on Tuesday also mentioned changing the name of the Gulf of Mexico to the Gulf of America.

But none of those options ranks with leaving open the possibility of military force to take the Panama Canal and especially Greenland.

Greenland is a semiautonomous territory under the Kingdom of Denmark, which is a member of NATO. That makes Greenland also part of NATO. It was further integrated into the alliance when it got its first envoy to NATO in 2023.

The reason this matters is because the centerpiece of NATO is a mutual-defense agreement, known as Section 5, in which NATO member nations are obliged to regard an attack on any NATO ally as an attack on all of NATO.

Victoria Herrmann, a senior fellow at the Arctic Institute, a think tank focused on policy in the arctic, said Greenland would benefit from Section 5.

“If the United States chose to use military force against Greenland and in turn the Kingdom of Denmark, it would be an attack against a member of NATO, and an attack on one is an attack on all,” Herrmann said.

Precisely what that might mean isn’t clear, as NATO’s charter doesn’t spell out what NATO countries must do in response. But generally speaking, it’s understood that NATO countries would defend one another in such a situation.

In other words, Trump is at least rhetorically leaving open the possibility of a situation that could result in NATO going to war with itself.

It sounds ridiculous and will in all likelihood never come to pass. But even the implied threat is something.

And at the very least, Trump’s comments might lead to some discussion of Section 4 of NATO. That section states that the alliance “will consult together whenever, in the opinion of any of them, the territorial integrity, political independence or security” of another member is threatened.