Greenland live legal updates: Why Donald Trump’s coercive trade threats risk violating international law and the transatlantic alliance

The latest escalation by United States President Donald Trump over Greenland marks one of the most legally fraught and geopolitically destabilising episodes in modern transatlantic relations. By threatening to impose punitive tariffs on eight European allies unless they acquiesce to the United States acquiring Greenland, the American president has fused trade policy, territorial ambition and security rhetoric into a single act of coercive diplomacy that sits uneasily, and in several respects unlawfully, within the architecture of international law.

What began as political theatre has now hardened into a concrete threat: a ten per cent tariff on goods from Denmark, Norway, Sweden, France, Germany, the United Kingdom, the Netherlands and Finland from 1 February, rising to twenty five per cent from 1 June, to remain in force until what Trump described as the “complete and total purchase of Greenland”. This ultimatum has triggered emergency diplomatic consultations in Brussels, protests in Copenhagen and Nuuk, military deployments by European states to Greenland, and an unusually unified denunciation by European leaders who warn of a “dangerous downward spiral”.

From the perspective of public international law, trade law and the law governing the use of force, this episode is not merely provocative. It is potentially unlawful.

Greenland is an autonomous territory within the Kingdom of Denmark. Its status is governed by the Danish constitution and the Greenland Self Government Act of 2009, which recognises the Greenlandic people as a people under international law and affirms their right to self determination. Any transfer of sovereignty would require the consent of the people of Greenland, expressed through democratic means. Opinion polling indicates that eighty five per cent of Greenlanders oppose joining the United States, a position echoed in mass demonstrations in Nuuk and Copenhagen and by Greenland’s prime minister Jens Frederik Nielsen, who marched with protesters carrying signs declaring that Greenland is not for sale.

At the international level, sovereignty and territorial integrity are foundational principles enshrined in Article 2(1) and Article 2(4) of the United Nations Charter. While Article 2(4) is most commonly associated with the prohibition on the use of armed force, the broader principle of non intervention, articulated in customary international law and codified in the 1970 Declaration on Friendly Relations, also prohibits states from using economic or political coercion to force another state to surrender its sovereign rights.

Threatening punitive trade measures unless Denmark and its allies accept the transfer of territory is difficult to reconcile with this rule. The International Court of Justice, in cases such as Nicaragua v United States, has made clear that coercive measures designed to compel a state to adopt a particular political outcome fall within the prohibition on intervention in the internal or external affairs of another state.

When Trump previously declared that the United States could obtain Greenland “the easy way or the hard way”, he ventured even closer to the red line of unlawful threat of force. European leaders have now reacted accordingly. The joint statement by the United Kingdom, Denmark, Finland, France, the Netherlands, Norway and Sweden explicitly invokes sovereignty and territorial integrity as principles they “stand firmly behind”. European Commission president Ursula von der Leyen has reiterated that these principles are fundamental to international law. Finnish president Alexander Stubb and Swedish prime minister Ulf Kristersson have warned that tariffs in this context amount to blackmail.

From a trade law perspective, the threatened measures are equally problematic. The United States is bound by the World Trade Organization agreements, including the General Agreement on Tariffs and Trade. These instruments require members to apply tariffs in a non discriminatory manner under the most favoured nation principle and to respect bound tariff ceilings.

A unilateral increase to twenty five per cent targeted specifically at countries opposing a territorial acquisition would almost certainly breach these obligations unless justified under a recognised exception. The United States might seek to invoke the national security exception under Article XXI of GATT, arguing that Greenland is critical for missile early warning systems and Arctic security. However, the use of that exception as a bargaining chip to compel the sale of territory would stretch the concept of good faith to breaking point.

The WTO dispute settlement body has, in recent years, narrowed the scope for abuse of the security exception, most notably in the Russia Transit case, holding that states cannot simply label any measure as security related to escape scrutiny. A tariff explicitly linked to a demand for territorial transfer would be vulnerable to legal challenge by the European Union and its member states.

This legal fragility is already feeding into European domestic politics. Manfred Weber, leader of the European People’s Party group in the European Parliament, has stated that Trump’s threats make ratification of last year’s EU US trade agreement politically impossible at this stage. That agreement set a general US tariff of fifteen per cent on EU goods while granting zero per cent tariffs on certain American exports to the EU. Weber has called for those concessions to be put on hold.

Gregory Meeks, the ranking Democrat on the House Foreign Affairs Committee, has announced his intention to introduce a resolution to terminate what he describes as “illegal and absurd tariffs”, accusing the president of manufacturing a foreign crisis while ignoring domestic economic pressures.

NATO, collective defence and the militarisation of diplomacy

The legal stakes extend beyond trade into the law of collective security. Greenland’s strategic location between North America and the Arctic makes it valuable for early warning radar systems and maritime surveillance, but it is already covered by NATO’s collective defence framework. Denmark is a founding member of NATO, and the alliance’s Article 5 obligation extends to Greenland.

European governments have stressed that Arctic security should be a joint NATO responsibility, not a pretext for unilateral territorial acquisition. France, Germany, Sweden, Norway, Finland, the Netherlands and the United Kingdom have dispatched small contingents of troops to Greenland in what they describe as a reconnaissance mission, a symbolic but potent signal that they regard the territory as European and Danish, not negotiable.

US Senator Mark Kelly, a former Navy pilot, has captured the reputational damage succinctly. He has written that European troops are arriving “to defend the territory from us”, warning that the president is leaving the United States isolated, surrounded by adversaries and estranged from allies.

The US ambassador to the United Nations, Mike Waltz, has argued that Denmark lacks the capacity to secure Greenland adequately and that Greenlanders would be safer under American control. Yet this argument, even if sincerely held, does not confer any legal entitlement to acquire territory, nor does it override the right of self determination.

Beyond the formal legality, the threatened tariffs risk significant economic harm. The International Monetary Fund has repeatedly warned that uncertainty itself is economically corrosive. Its managing director, Kristalina Georgieva, has described uncertainty as the defining feature of the Trump era.

The timing is particularly damaging for Europe. France is grappling with a budgetary crisis, Germany is seeking recovery after stagnation in 2025, and the United Kingdom’s chancellor Rachel Reeves has only just begun to hope for a modest upturn after a difficult year. A sudden tariff shock would disrupt supply chains, depress investment and almost certainly feed inflationary pressures within the United States itself, raising prices for American consumers.

Norwegian prime minister Jonas Gahr Stoere has cautioned against a trade war that spirals out of control, warning that no one benefits. Finnish prime minister Petteri Orpo has emphasised that disputes among allies should be resolved through discussion, not pressure, and that tariffs would harm both sides.

The diplomatic response has been swift and unusually unified. UK prime minister Keir Starmer has called the move completely wrong. French president Emmanuel Macron has labelled it unacceptable. European Council president Antonio Costa has stated that the European Union will be firm in defending international law within the territory of its member states. EU foreign policy chief Kaja Kallas has observed that China and Russia are the only beneficiaries of divisions among allies.

Protests in Greenland and Denmark have reinforced the domestic legitimacy of European resistance. Demonstrators in Copenhagen carried placards reading “Hands off Greenland” and “Greenland for Greenlanders”. Camilla Siezing of the Inuit umbrella organisation declared that respect for the Danish Realm and Greenland’s right to self determination is non negotiable. In Nuuk, protesters marched to the US consulate, joined by Greenland’s prime minister.

The rhetoric from Washington, by contrast, has been inflammatory. Deputy attorney general Todd Blanche has accused Danish and European leaders of playing a dangerous game. Trump himself has framed the dispute in existential terms, claiming that the “safety, security and survival of our planet” are at stake.

Such language may play well domestically, but in legal and diplomatic terms it represents a troubling erosion of post war norms. Since 1945, the prohibition on acquiring territory by coercion has been one of the few near universal rules of international conduct. Undermining it in the Arctic risks encouraging similar behaviour elsewhere, from Eastern Europe to the South China Sea.

A test case for the rule based order

This confrontation over Greenland is therefore more than a bilateral spat. It is a stress test for the rule based international order. If economic coercion can be used openly to force the transfer of territory from an ally, then the distinction between law and power politics becomes dangerously thin.

The immediate legal avenues are clear. The European Union and affected states can challenge the tariffs at the World Trade Organization. Denmark can invoke the principles of non intervention and self determination in diplomatic and, if necessary, judicial forums. The United Nations General Assembly could be seized of the matter if threats of force are renewed.

Yet law alone cannot resolve what is fundamentally a crisis of political restraint. As matters stand, the combination of threatened tariffs, military posturing and explicit linkage to territorial acquisition places the United States on a collision course with its own treaty obligations, its closest allies and the legal principles it has historically championed.

In that sense, the warnings from European leaders about a dangerous downward spiral are not rhetorical excess. They are a sober assessment of what happens when trade policy is weaponised to rewrite borders. If this approach prevails, it will not merely reshape the Arctic. It will weaken the legal foundations of international order itself.