U.S. Attack on Greenland Would Spell End of NATO, Danish PM Warns

COPENHAGEN — Danish Prime Minister Mette Frederiksen issued a stark warning Monday that any military attack by the United States on Greenland — an autonomous territory within the Kingdom of Denmark and a NATO member — would effectively terminate the North Atlantic Treaty Organization (NATO) and unravel the post–World War II security order that has sustained Western defence cooperation for decades.

Speaking to Danish broadcaster TV2, Frederiksen underscored the gravity of U.S. President Donald Trump’s recent rhetoric regarding Greenland, stating that “if the United States chooses to attack another NATO country militarily, then everything stops — including our NATO and thus the security that has been provided since the end of the Second World War.”

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Escalation Amid Arctic Strategic Competition

The warning comes against the backdrop of heightened geopolitical tensions involving the United States’ renewed expressions of interest in Greenland’s strategic location and natural resources. In recent days, Trump reiterated that the United States “needs Greenland from the standpoint of national security,” citing concerns about Russian and Chinese activity in the Arctic.

Greenland sits astride critical Arctic sea lanes and hosts advanced U.S. defence infrastructure, including the Pituffik Space Base, which supports ballistic missile warning and space surveillance operations for both the United States and NATO. Despite this longstanding military cooperation, Danish leaders insist that Greenland’s future is a matter for the Danish realm and the island’s people — not for external powers to decide.

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Danish and Greenlandic Rebuttal

Alongside Frederiksen’s warning, Greenland’s Prime Minister Jens-Frederik Nielsen condemned any notion of annexation as “unacceptable” and urged Washington to abandon what he described as “fantasies about annexation.” He stressed that the island’s democratic institutions and sovereignty must be respected.

European allies have rallied in support of Denmark’s position. Senior officials in Sweden, Norway, Finland and across the EU have emphasized the principles of sovereign territorial integrity and self-determination, while cautioning against any military adventurism among NATO partners.

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Broader Implications for NATO

Frederiksen’s comments expose a rare moment of intra-alliance tension that could reshape the contours of Western defence cooperation. NATO’s foundational principle of collective defense under Article 5 presupposes that an attack on one member is an attack on all. A unilateral move by the United States against Greenland — itself covered under Denmark’s NATO protection — would place European members in an unprecedented dilemma.

Analysts suggest that the broader implications extend beyond Nordic security and Arctic geopolitics: a credible threat from a leading NATO member could undermine alliance cohesion at a time when Russia’s military posture remains assertive and China expands its global strategic footprint.

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White House Stance and U.S. Political Context

The White House has not formally backed away from Trump’s statements, and some senior U.S. political figures have publicly advocated for stronger American control or influence in Greenland — framing the issue in terms of national interest and hemispheric security. Critics argue, however, that such rhetoric risks eroding alliances that remain foundational to U.S. strategic strength.

As the situation evolves, the delicate balance between alliance solidarity and national prerogatives is being tested, raising urgent questions about the future of transatlantic security frameworks.

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Photo Credit: IISD/ENB / Diego Noguera