Marcus Walker

Leaving NATO formally would be legally difficult.

Congress passed a law in 2023 that said the president basically is forbidden from pulling out of NATO unless it's authorized by two-thirds of the Senate or an act of Congress that would have to pass the House and the Senate.

On the other hand, Trump's Justice Department in his first term

came up with a legal opinion that said the president has the power to unilaterally abrogate treaties.

So those two things clash, and if Trump tried to pull out of NATO, it would almost certainly end up in court.

However, the point about NATO is that it's not a legalistic alliance.

It's basically a political promise among a group of 30 or so countries to defend each other.

So in the case of an attack on a NATO member, the question would be in the air, would the US go to war to defend its European allies?

Even if a compromise is found on the Greenland issue, things will never be the same.

A line has been crossed here because of Trump's willingness really to consider all options, including force, against the U.S.

's own allies.

Well, there has been a flurry of diplomacy both in public and in private between Trump and other White House officials and the European side.

The Europeans are planning an emergency summit of European Union leaders on Thursday in Brussels.

Before that, it's likely that Trump will meet some European leaders in Davos.

Trump has said he will meet various parties without specifying whom at the World Economic Forum.

after which it remains completely unclear whether Trump will go ahead with his threat to impose tariffs on some European countries from the 1st of February and whether it will escalate or whether some solution will be found in the meantime.

It's clear from the communications in the last few hours or overnight that Trump is not backing down from his demand that the US should own Greenland and should take it over

completely.

Even though Trump said that he had a good conversation with NATO Secretary General Mark Ritter, he emphasized that he needs to own Greenland, in his view.

At the same time, Trump has said further critical things about other European allies.