Danish Prime Minister Warns U.S. Takeover of Greenland Would End NATO

Denmark’s prime minister, Mette Frederiksen, warned on Jan. 5–6 that any U.S. takeover of Greenland would amount to a fundamental rupture of the North Atlantic Treaty Organization and the post–World War II security order it underpins. Frederiksen framed the risk in uncompromising terms, saying, “If the United States decides to attack another NATO country, then everything would stop, that includes NATO and therefore post-World War II security.” She added that “I believe that the U.S. president should be taken seriously when he says that he wants Greenland.”

The remarks followed fresh public entreaties by the U.S. president for Greenland to come under direct American control and came in the immediate aftermath of a weekend U.S. military operation in Venezuela. That operation, and reports linking it to the abduction of Venezuela’s leader, have heightened concerns in Copenhagen about the potential for unilateral U.S. use of force and the precedent it would set for alliance politics.

Greenland, an autonomous territory of the Kingdom of Denmark, sits astride key Arctic sea lanes, harbors significant mineral wealth and strategic value, and is home to an Indigenous population with a long history of semi-autonomy and cultural distinctiveness. Its status makes any foreign effort to assert control both a diplomatic flashpoint and a legal minefield. Denmark’s chief envoy in Washington sought to underline that point by insisting that “we expect full respect for the territorial integrity of the Kingdom of Denmark.”

In Nuuk, Greenland’s head of government, Jens-Frederik Nielsen, moved to calm local residents and preserve ties with the United States, urging Greenlanders not to “panic” and calling for “good cooperation” with Washington. The contrast between Copenhagen’s alarm and Nuuk’s conciliatory posture reflects the delicate balance between protecting sovereignty and maintaining practical relationships with the United States, which remains a major security partner and economic interlocutor for the territory.

Frederiksen’s warning crystallizes a broader dilemma for NATO and international law. An attempt by one member or by the United States to absorb territory of a fellow member or its associated realm would confront Article 5 obligations, fracture alliance cohesion and violate fundamental principles of territorial sovereignty enshrined in the UN Charter. The prospect of a NATO member striking another or seeking territorial acquisition would force other allies to choose between political, legal and military responses, with unpredictable consequences for collective defense and deterrence.

Beyond legalities, the episode illuminates evolving geopolitics in the Arctic, where competition over resources, new shipping routes and military positioning have accelerated. For Greenlanders and for smaller NATO members, the incident underscores how great power rhetoric and unilateral action can override local concerns and historical commitments unless checked by firm diplomacy and legal clarity.

Copenhagen is now pressing for explicit assurances that Greenland’s status will be respected, while allies and partners watch how Washington responds. The coming days will test whether diplomatic channels can contain the fallout or whether Frederiksen’s bleak assessment about the deterioration of the NATO order proves prescient.