Since late 2025, political friction between the United States and Denmark regarding the sovereignty of Greenland has escalated, fueled by the Trump administration’s repeated强硬 statements that it “leaves all options on the table.” Trump has made no secret of his desire for Greenland, arguing that the island’s unique geopolitical and commercial value could significantly advance U.S. interests in the Arctic. He also seeks to use the acquisition of Greenland to demonstrate “achievements” in foreign policy, thereby masking a domestic agenda marked by few legislative accomplishments and numerous scandals, in an effort to garner public support and take a calculated risk ahead of the upcoming midterm elections.
The Greenland crisis fully embodies the unilateralist nature of the Trump administration’s “America First” policy. Its extremely assertive, hegemonic, and bullying style has provoked anger within NATO. Regardless of how this crisis ultimately ends, it has already profoundly impacted NATO’s operational model.
NATO’s Dilemma
Should the Greenland crisis escalate, NATO, as the institutional hub of the transatlantic alliance and a fundamental pillar of the European security order, would be the first to face severe challenges. On January 5, 2026, Danish Prime Minister Mette Frederiksen stated publicly that Trump’s renewed interest in controlling Greenland placed “unacceptable pressure” on Denmark and Greenland. She warned that if the U.S. took military action against a NATO ally, “everything would be over.” On January 13, Greenland’s Premier Múte Bourup Egede, speaking at a joint press conference in Copenhagen with Prime Minister Frederiksen, stated that Greenland is part of the Danish Realm with self-government within the kingdom and “will not be owned by the U.S., will not be ruled by the U.S., and will not become part of the U.S.”
As a self-governing territory of Denmark, Greenland theoretically falls under the collective security umbrella defined by Article 5 of the North Atlantic Treaty (the collective defense clause). Article 5 stipulates that an armed attack against one NATO member shall be considered an attack against all members. This clause outlines the collective security obligations of member states and is foundational to the formation and operation of the transatlantic collective security system. However, the article does not anticipate scenarios involving military conflict between member states. Regardless of which of the following scenarios emerges from an escalation of the Greenland crisis, NATO’s foundations would be damaged:
- If NATO claims that Article 5 does not envision intra-alliance military conflict and, under U.S. pressure, chooses inaction, the legitimacy and effectiveness of Article 5 would be significantly undermined.
- If NATO decides to invoke Article 5 to intervene in the Greenland crisis, it would need to urgently adopt supplementary measures. Given NATO’s consensus-based decision-making principle on major issues, achieving this would be extremely difficult under current internal circumstances. The U.S., having instigated the crisis, would certainly not accept NATO constraining its actions, and European members would struggle to form an effective intra-alliance counterbalance to the U.S. Consequently, Article 5 faces an applicability problem.
During Trump’s first term, relations between the U.S. and other NATO members fractured, hindering the alliance’s normal functioning, a situation famously described by French President Emmanuel Macron as “brain death.” Despite active repair efforts during the Biden administration, the impact of the Ukraine crisis, and compromises by European members at the June 2025 Hague summit that maintained a veneer of NATO unity, the Trump administration’s devaluation of the transatlantic alliance, disregard for European allies’ interests, and particularly its exclusion of European nations from the Ukraine crisis peace process, have re-exposed the reality of divergent interests between the U.S. and Europe. The ongoing Greenland crisis has further escalated transatlantic tensions.
UK Prime Minister Keir Starmer has publicly stated that Greenland’s future belongs entirely to its people and the Danish Realm. Germany has proposed establishing a joint NATO “Arctic Sentry” mission, modeled on the “Baltic Sentry” approach, integrating frigates, early warning aircraft, and rapid reaction forces, primarily tasked with monitoring and deterrence in and around Greenland. Regardless of the final outcome, this crisis marks the first time since NATO’s founding that the U.S., the alliance’s “brain” and guiding force, has openly threatened and coveted the territory of an ally. This will severely undermine NATO’s cohesion, weaken U.S. credibility within the transatlantic alliance, and erode European allies’ confidence in U.S. security guarantees. Consequently, the risk of NATO relapsing into “brain death” has significantly increased.
A Disruptive Change to NATO’s Internal Cooperation Model
Since the Greenland crisis escalated, although several European countries have expressed solidarity with Denmark, these have largely been symbolic gestures lacking substantive involvement. The EU and European nations are clearly reluctant to become embroiled in a sharp dispute with the U.S. by supporting Denmark’s defense of its rights over Greenland. However, the Trump administration has not abandoned its claim to Greenland simply because these nations have adopted an “appeasing” attitude towards the U.S. European countries will be forced to confront a disruptive change in NATO’s internal cooperation model. Currently, two trends are becoming increasingly clear.
First, Trump is progressively strengthening the “disciplining” of European nations, aiming to transform the U.S. from NATO’s guiding force into its “absolute dominant power.” The Greenland crisis serves as a brutal stress test for European countries. Trump, employing his customary “maximum pressure” tactics, continuously forces European nations to reveal the limits of their appeasement and compromise towards the U.S. Since Trump’s return to office, European countries have already made significant concessions to the U.S. on major issues such as the 5% minimum defense spending target and the Ukraine crisis peace process, with European strategic autonomy gradually degrading into “autonomy sanctioned by the U.S.” If European countries choose complete capitulation on the Greenland issue, sacrificing Denmark to maintain stable U.S.-Europe relations, NATO would be forced into a difficult choice between “America First” and “collective security.” It could potentially transform entirely into a hegemonic tool for the U.S., leading to the “dual termination” of European strategic autonomy in both form and substance.
Second, NATO’s defense focus is effectively becoming “dual-tracked.” In late 2025, NATO transferred defense planning responsibilities for Denmark, Sweden, and Finland from the Joint Force Command based in the Netherlands to the Joint Force Command based in Norfolk, Virginia, USA, to enhance rapid response capabilities in high-latitude regions. Consequently, the Norfolk Command now has full responsibility for the security and defense of NATO’s northern flank, diminishing the autonomous decision-making power of European allies in the North Atlantic-Arctic region. Furthermore, the U.S. plans to deploy the “Golden Dome” missile defense system in Greenland and seeks “whatever military access it desires.” These developments indicate that the Trump administration is reshaping the collective defense mechanism of NATO into a tool for U.S. unilateralist strategy, rather than prioritizing and primarily focusing on European defense responsibilities as in the past.
Since Trump’s return to office, his administration has shown profound disregard for NATO and the transatlantic relationship. However, at least at this stage, the U.S. cannot completely abandon NATO. For European nations, leveraging NATO’s institutional framework to constrain U.S. actions, while the U.S. has not yet fully dominated the alliance, represents a relatively low-cost but practical and rational choice.
The Trump administration initially framed the Greenland issue as a bilateral matter between the U.S. and Denmark, deliberately circumventing NATO mechanisms in an attempt to independently secure military base construction and resource control. However, a breakthrough compromise was reportedly negotiated between Trump and NATO Secretary General Mark Rutte during the World Economic Forum in Davos, Switzerland, in January. The agreement reportedly involves a U.S. commitment not to use military means, in exchange for NATO allowing the U.S. effective control over Greenland’s resources and granting the U.S. unconditional military access rights.