Washington’s claims over Greenland call into question the very logic of NATO’s existence and strike at the foundations of the alliance. This was the assessment voiced by Polish Prime Minister Donald Tusk as he spoke with reporters ahead of his departure for a meeting of European leaders in Paris.

Tusk made it clear that no NATO member can threaten or attack another without stripping the alliance of its meaning. In his view, any such scenario would fundamentally contradict the principles on which NATO is built.

He also signaled that Denmark can count on the solidarity of Europe as a whole. At the same time, the Polish prime minister warned that officials in Washington should fully understand the consequences of statements of this kind. Actions or rhetoric perceived as undermining NATO’s core principles, he said, would find no understanding in any European capital.

Tusk’s remarks followed comments by U. S. President Donald Trump. On January 4, Trump said that U.S. control over Greenland was necessary for national security reasons. He described the issue as strategic, pointing to the presence of Russian and Chinese vessels in the area and arguing that Denmark was unable to ensure an adequate level of security for the territory.

This was not the first time Trump had raised the Greenland issue. During his first presidential term, he proposed purchasing the island. Later, in March 2025, he publicly expressed confidence that its annexation was possible, warning that Copenhagen could face trade tariffs if it refused. Danish authorities have consistently rejected these claims. Prime Minister Mette Frederiksen has repeatedly stressed that Greenland remains part of the Danish kingdom.