Would NATO fight a U.S. invasion of Greenland?

Europe spent much of 2025 scrambling to bolster its defenses against Russia — but just a week into the new year, it’s being forced to rethink security once again amid President Donald Trump’s threats to annex Greenland.

Trump has been ramping up calls for Greenland — a semi-autonomous Danish territory — to be brought under Washington’s control. This week, the White House said Trump was considering various options to make it happen, including military action.

Greenland, the world’s largest island, is rich in untapped mineral resources. Although geographically positioned on the North American continent, it is politically part of Europe.

Acquiring the island would be no mean feat. Aside from political obstacles both at home and abroad, any attempt to take the territory by force would pit the U.S. against its NATO allies.

In an interview with CNN earlier this week, top Trump aide Stephen Miller suggested no European country would be prepared to put up a fight to protect Greenland. Although not explicitly ruling out the possibility of U.S. military action in Greenland, he argued that “there’s no need to even think or talk about this in the context of a military operation [because] nobody’s going to fight the United States militarily over the future of Greenland,” pointing to the island’s small population.

For its part, Denmark and Greenland are taking of U.S. military action seriously. In a statement on Tuesday evening, Danish Defense Minister and Deputy Prime Minister Troels Lund Poulsen said Denmark would spend 88 billion Danish kroner ($13.8 billion) rearming Greenland, given “the serious security situation we find ourselves in.”

Despite that apparent willingness from Denmark to defend Greenland, analysts told CNBC they do not believe European forces would ever open fire on American troops.

Edward R. Arnold, a senior research fellow at British defense think tank Royal United Services Institute, told CNBC in a call on Tuesday that the White House does have the military power to move in on Greenland and, if it wanted to, could do so “really quite quickly.”

But Washington would not have to launch an operation like the one seen in Venezuela over the weekend, according to Arnold, because “it would be completely unopposed.”

“What European military commander is going to open force on a U.S. troop transport coming into Greenland?” he said. “That would start an inter-NATO war, potentially. And the U.S. knows that.”

The United States has, by far, the greatest military strength of any NATO member. In 2024, NATO estimated that the U.S. had 1.3 million military personnel, compared to the rest of the alliance’s collective 2.1 million personnel. The next biggest military staff belonged to Turkey, which had an estimated…