How NATO works at a time when Trump is threatening to seize Greenland

Trump’s Greenland Ambitions Create Unprecedented NATO Tension

President Donald Trump’s persistent declarations about acquiring Greenland have escalated into a diplomatic crisis that threatens to undermine the foundation of the North Atlantic Treaty Organization (NATO). His recent statement that “One way or another, we’re going to have Greenland,” coupled with the White House’s refusal to rule out military action, has sent shockwaves through the alliance.

Greenland, a semi-autonomous territory within the Danish realm, has become the center of a geopolitical controversy that challenges NATO’s core principles. Danish Prime Minister Mette Frederiksen responded with a stark warning: “If the United States chooses to attack another NATO country militarily, then everything stops… including our NATO.”

This standoff represents an unprecedented scenario in NATO’s 75-year history. While the alliance has weathered internal disagreements before, notably between Greece and Turkey, it has never faced the prospect of its most powerful member potentially annexing territory from another ally.

Trump has justified his interest in Greenland as a strategic move to prevent Russian or Chinese influence in the region. “Making a deal would be easier,” Trump noted, suggesting his preference for a negotiated acquisition while leaving military options on the table.

NATO was established in 1949 with 12 founding nations to counter Soviet threats during the Cold War. Its membership has since expanded to 32 countries, with Sweden being the most recent addition in 2024, driven by concerns about Russian aggression. The alliance officially identifies Russia and international terrorism as its principal threats—not internal conflicts between member states.

The cornerstone of NATO’s collective security is Article 5, which establishes that an attack on one member is considered an attack on all. This provision has only been invoked once—following the September 11, 2001, terrorist attacks against the United States. While Trump has previously affirmed his commitment to Article 5, he has also questioned defending allies who don’t meet defense spending targets.

Experts note that Article 5 would be ineffective in a U.S.-Denmark conflict since it requires unanimous approval to activate. Denmark could potentially invoke Article 4, which allows for consultations when a member’s security is threatened, but this wouldn’t automatically lead to action.

Senior U.S. and Danish officials were scheduled to hold talks Wednesday to address the growing tension. The situation threatens to divide NATO in ways reminiscent of the 2003 Iraq War, when the alliance split between countries supporting U.S. military action and those opposed.

As NATO’s dominant member, the United States provides unparalleled military resources and leadership. The alliance’s operational effectiveness would be severely compromised without American participation, making it virtually impossible for any ally to oppose U.S. actions militarily.

Former Dutch Prime Minister Mark Rutte, who leads NATO’s civilian operations as Secretary General, has carefully avoided criticizing Trump or acknowledging the crisis. When questioned about Greenland tensions on Monday, Rutte deflected, stating: “All allies agree on the importance of the Arctic and Arctic security because we know that with sea lanes opening up there is a risk that the Russians and the Chinese will be more active.”

When directly asked if NATO was experiencing a crisis over Greenland, Rutte responded: “No, not at all.”

The situation presents a fundamental challenge to NATO’s structure, where the U.S. holds considerable sway. NATO’s military headquarters in Mons, Belgium, is traditionally commanded by an American officer—currently Air Force Lt. Gen. Alexus Grynkewich, who ultimately reports to Trump as commander in chief.

As this diplomatic crisis unfolds, the long-term implications for transatlantic relations and NATO’s future cohesion remain uncertain. What is clear is that Trump’s Greenland ambitions have created an unprecedented test for an alliance built on mutual defense against external threats, not aggression between its own members.