As Trump threatens to seize Greenland, the trans-Atlantic alliance that has underpinned Western security for nearly eight decades is facing one of its most serious tests since its founding. European and Canadian leaders, long accustomed to American leadership within NATO, are now grappling with the extraordinary possibility that the alliance’s most powerful member could move against the territory of another.
Over the past year, President Donald Trump has repeatedly pressured NATO through threats of withdrawal, demands for increased defense spending, and blunt warnings that the United States will no longer underwrite European security without concessions. Those tactics, while destabilizing, remained within the bounds of political coercion.
The Greenland crisis has changed that calculation.
Trump’s suggestion that the United States could seize control of Greenland — potentially by military force — has raised alarms across allied capitals that the president may be prepared to cross a red line that could fracture NATO beyond repair.
A small territory at the center of a global alliance
Greenland, a vast Arctic island with a population of about 56,000, is a semiautonomous territory of Denmark, one of NATO’s founding members. While Denmark retains responsibility for foreign and defense policy, Greenland governs its internal affairs and has the legal right to pursue independence through a referendum.
Despite its small population, Greenland holds enormous strategic significance. Located between North America and Europe, it sits astride key Arctic sea routes and hosts critical infrastructure, including a U.S. military base used for missile warning and space surveillance.
That strategic value has increasingly drawn the attention of Washington, particularly as climate change opens Arctic waters to greater Russian and Chinese activity.
High-stakes diplomacy in Washington
On Wednesday, top diplomats from Denmark and Greenland are scheduled to meet with Vice President JD Vance and Secretary of State Marco Rubio at the White House in what Danish officials describe as a crucial effort to defuse tensions.
“This will be a meeting room where we can look each other in the eye and talk about these things,” Danish Foreign Minister Lars Lokke Rasmussen said Tuesday, signaling the seriousness of the moment.
Yet even as diplomats prepared for talks, Trump escalated his rhetoric.
“NATO should be leading the way for us to get Greenland,” the president said hours before the meeting, reframing his demands as a test of alliance loyalty rather than a unilateral American ambition.
In a social media post, Trump argued that NATO’s effectiveness depends on U.S. military dominance and insisted that Greenland must fall under American control.
“Without American military power, NATO would not be an effective force or deterrent — not even close,” he wrote. “NATO becomes far more formidable and effective with Greenland in the hands of the UNITED STATES. Anything less than that is unacceptable.”
Coercion has worked before — but at what cost?
Trump’s past threats against NATO have produced tangible results. After he repeatedly warned that the United States might leave the alliance, member states last summer agreed to accelerate defense spending increases.
Similarly, Trump initially paused U.S. military aid to Ukraine, only to resume shipments after NATO allies proposed financing American weapons instead of relying on donations.
Those episodes reinforced the perception that Trump uses brinkmanship as a negotiating tactic — pushing allies to the edge in order to extract concessions.
But the Greenland issue is different, analysts say, because it involves territorial sovereignty rather than budgetary commitments.
“This isn’t about money,” said Sten Rynning to The New York Times, a NATO analyst and professor at the University of Southern Denmark. “It’s about borders, alliances, and the basic rules that hold NATO together.”
The Article 5 dilemma
At the heart of the crisis is Article 5 of NATO’s founding treaty, which states that an attack on one member is considered an attack on all.
The provision has been invoked only once, after the terrorist attacks on the United States on September 11, 2001. It has never been tested in a scenario where one NATO member attacks another.
The treaty offers no guidance for such a situation.
“If the United States were to invade Greenland, it would without question block NATO from responding,” Mr. Rynning said. “And NATO would be stuck.”
That paralysis, he warned, could open the door for adversaries like Russia to exploit the chaos.
“If NATO cannot act when its credibility is tested,” he said, “then it is effectively defunct.”
‘It would be the end of NATO’
Rob Bauer, a retired Dutch admiral who until last year served as NATO’s most senior military officer, expressed skepticism that Trump would actually follow through on his threats.
“Because it is the end of NATO,” Admiral Bauer said in an interview. “And I don’t think that is something the United States ultimately wants.”
He suggested that Trump’s rhetoric is more likely aimed at forcing NATO to take Arctic security more seriously — an area that Washington has long argued is under-prioritized.
Still, even as a negotiating tactic, the language has unsettled allies.
Arctic security moves to the forefront
The uproar has already had one clear effect: Arctic security has surged to the top of NATO’s agenda.
As melting ice opens new shipping lanes, Russian and Chinese naval and commercial activity in the Arctic has increased. Allied officials now broadly agree that NATO must expand its presence in the region to protect sea routes, undersea cables, and strategic infrastructure.
“We all agree in NATO that when it comes to the protection of the Arctic, we have to work together,” NATO Secretary General Mark Rutte said Tuesday. “And that’s exactly what we are doing.”
For years, Denmark has been cautious about inviting large-scale NATO operations around Greenland, partly to avoid friction with the United States. That reluctance is now fading as the security environment evolves.
Lessons from Trump’s first term
Trump also raised the idea of buying Greenland in 2019, but the controversy faded after diplomatic engagement with Denmark.
Kay Bailey Hutchison, who served as Trump’s ambassador to NATO during his first term, said the renewed focus reflects changing strategic realities rather than a sudden obsession.
“There’s much greater awareness now of Chinese and Russian activities,” she said. “And Greenland’s proximity to the Atlantic makes it more important from a U.S. security standpoint.”
Ms. Hutchison stressed, however, that sovereignty remains non-negotiable.
“Denmark absolutely has the right to make the foreign policy decisions regarding Greenland,” she said, adding that she doubts military force is a realistic option.
Congress as a potential check
Within the United States, support for NATO remains strong across party lines, even as Trump pushes its boundaries.
“If the president tried to undermine NATO by controlling Greenland, I think Congress will stop him,” said Senator Tim Kaine, Democrat of Virginia.
A bipartisan delegation of U.S. lawmakers is scheduled to travel to Denmark later this week to signal support for the alliance.
Still, Trump’s position has supporters. Representative Randy Fine, a Republican from Florida, introduced legislation this week that would authorize the president “to take whatever steps necessary to annex or acquire Greenland.”
NATO under pressure — but resilient?
The Greenland crisis comes at a particularly fragile moment for the alliance. European members are struggling to sustain support for Ukraine, counter Russian hybrid warfare, and prepare for a possible reduction in U.S. troop levels on the continent.
Yet NATO has weathered severe internal tensions before, including France’s withdrawal from NATO’s integrated military command in the 1960s and repeated disputes between Turkey and Greece.
“Sometimes the ice is thin, and sometimes the ice is thick,” Admiral Bauer said. “This is rough weather — but not the first time.”
The difference now, many officials say, is that the challenge comes from within.
As Trump threatens to seize Greenland, allies are left navigating an uncomfortable reality: NATO’s greatest strength — American power — may also be its greatest vulnerability.
Whether diplomacy can pull the alliance back from the brink remains an open question.
