Europe live legal updates: Trump’s Greenland ultimatum

In an extraordinary and highly destabilising escalation of transatlantic relations, United States President Donald Trump has revived his much derided plan to acquire Greenland from the Kingdom of Denmark, coupling it with aggressive tariff threats against key European allies and significant diplomatic provocations ahead of the World Economic Forum in Davos. The resulting geopolitical shockwaves traverse international law, trade regulation, alliance solidarity, and the very foundations of modern multilateralism. This feature article provides the most exacting, expert legal and strategic appraisal of the situation as it stands, scrutinising Trump’s assertions, examining their legal grounding, and teasing out the wider implications for Europe, the World Trade Organization (WTO), NATO and the established liberal international order.

At the heart of the crisis is Trump’s repeated public insistence that the United States must “have” Greenland, coupled with threats to impose punitive tariffs on European Union member states and NATO allies unless Denmark accedes to cede control of the Arctic territory. He has articulated plans of levying tariffs starting at 10 per cent on goods from Denmark, Norway, Sweden, France, Germany, the Netherlands, Finland and the United Kingdom from 1 February, rising to 25 per cent on 1 June if no agreement to transfer Greenland is reached.

From a legal standpoint, the notion that Greenland might be sold or transferred to the United States is fundamentally inconsistent with established principles of international law. Article 2(4) of the United Nations Charter categorically prohibits the threat or use of force against the territorial integrity or political independence of any state. Sovereignty and territorial integrity are sacrosanct and non–derogable under customary international law, and the idea of overriding Denmark’s jurisdiction over an autonomous region through coercion or economic pressure sits uneasily with these norms.

Denmark is undisputedly sovereign over Greenland under international law. Greenland, though possessing extensive autonomous governance structures, is part of the Kingdom of Denmark and a constituent territory whose people hold Danish citizenship. Any transfer of sovereignty would require the unequivocal consent of the Danish state and, crucially, the people of Greenland, whose right to self–determination under international human rights law cannot be ignored. There is no indication that such consent exists or could be manufactured under duress, and any attempted transfer forced by tariff threats would likely be regarded as null and void in international tribunals. Moreover, the use of tariffs as leverage to induce cession of territory is tantamount to coercion prohibited under the Vienna Convention on the Law of Treaties, which invalidates treaties procured by force or duress. Although the United States is not a party to that convention, its principles are widely recognised as reflective of customary international law.

Trump’s linkage of tariff threats to diplomatic aims, such as compelling French President Emmanuel Macron to join a “Gaza Board of Peace”, further underscores the problematic conflation of trade policy with geopolitical bargaining. Threatening 200 per cent tariffs on French wine and champagne as leverage in diplomatic negotiations over the Middle East not only strains bilateral relations but also risks
dramatically contravening WTO rules on non–discrimination and proportionality. The WTO’s General Agreement on Tariffs and Trade (GATT) obliges members to adhere to Most-Favoured-Nation treatment and to ensure that any trade restrictions are justified under narrow exceptions such as national security under Article XXI, a provision whose invocation is itself contentious and largely untested before WTO dispute settlement bodies. Trump’s tariff threats rooted in his assertion that Greenland is vital to “national security” are likely to precipitate complex WTO litigation if implemented.

Economically, these measures represent a significant departure from established transatlantic cooperation. A bilateral EU–US trade agreement envisaged in mid-2025, which promised tariff liberalisation and stability, is now in jeopardy with ratification paused and trade tensions escalating. European Commission President Ursula von der Leyen and other EU leaders have warned that such unilateral levies amount to economic blackmail, undermining mutual prosperity and putting at risk a decades-long project of economic integration and cooperation with the United States.

European responses to date have been firm and multidimensional. Germany and France have rejected Trump’s tactics as coercive and unacceptable, signalling that Europe will not tolerate being “blackmailed”. Preparations for countermeasures, including the possible reinstatement of previously suspended tariffs on U.S. goods and activation of the EU’s Anti–Coercion Instrument, reflect a strategic shift in Brussels towards defending its economic sovereignty.

The invocation of the Anti–Coercion Instrument, a relatively new EU legal mechanism designed to counter economic coercion by third countries, marks a watershed in EU trade policy. This instrument allows the EU to adopt counter-measures against states that attempt to influence EU political or economic decision-making through coercive trade practices. Its use would be unprecedented against a longstanding ally and significantly raises the legal stakes of the current dispute.

From a geopolitical perspective, Trump’s rhetoric has unsettled NATO. NATO’s founding treaty embodies collective defence under Article 5, and Denmark’s deployment of troops to Greenland and the subsequent solidarity shown by allies demonstrate a collective commitment to Arctic security. Trump’s public refusal to rule out military options and his linking of NATO obligations to acquiescence in his territorial ambitions could erode the alliance’s unity and credibility.

There is also important domestic legal context within the United States. Tariff authority is subject to statutory constraints under U.S. law, primarily the Trade Act of 1974 and the Trade Expansion Act of 1962. Past U.S. court decisions have struck down tariff schemes where the executive overstepped its statutory mandate, underscoring that presidential tariff powers are neither unlimited nor immune from judicial review. Legal challenges to any new tariffs predicated on the Greenland ultimatum are highly probable and would add another layer of complexity to this dispute.

Looking ahead, the World Economic Forum in Davos represents a potentially consequential stage for diplomatic engagement or further escalation. Trump is reported to be meeting global business leaders and may encounter European leaders in informal discussions, with the Greenland issue likely dominating the agenda. Chinese Vice Premier He Lifeng’s presence underlines the broader geopolitical context, wherein other major powers are watching closely as U.S.–Europe relations undergo this acute stress test.

In sum, Trump’s Greenland gambit and associated tariff threats are legally tenuous, diplomatically fraught and strategically counterproductive. They challenge foundational principles of international law, strain the fabric of transatlantic alliances, risk significant retaliation at the WTO, and undermine trust between partners whose cooperation is central to global stability. Whether Europe responds with measured diplomatic pressure, robust legal challenges, or calibrated trade countermeasures, the coming weeks will be crucial in determining whether the rule based international order can withstand this most extraordinary provocation from a U.S. president. The implications extend far beyond Greenland’s icy expanse, touching the core of sovereign equality, alliance trust, and the enduring relevance of international legal norms to global governance in an era of renewed geopolitical contestation.