President Trump has been vocal about his interest in Greenland and talks between the US and Denmark on 14 January 2026 have not changed his position. Although the situation with Greenland is very different from that of Venezuela, not least as Denmark is a strong NATO ally, recent US actions in Venezuela and the seizure of foreign vessels suggest that the President's statements may carry real weight and that he is prepared to put his so-called "Donroe Doctrine", a policy of asserting US "pre-eminence" in the Western hemisphere, into action beyond South America.
In light of this, we bring together Danish, UK and US legal perspectives on what the implications could be of a US takeover of Greenland – however unlikely it may once have seemed – and the consequential risks that we should be considering now.
The status quo
Denmark's territorial claims to Greenland are recognised in the Danish Constitution and in a 1933 judgment of the Permanent Court of International Justice, which acknowledged that the US forfeited its claims over Greenland in 1916 as part of a transfer of the Danish West Indies to the US.
Greenland has its own government and parliament, with the right to decide which affairs of government it will take over from Denmark. Greenland already has the right to claim independence and become a sovereign state. Polls suggest that the general sentiment in Greenland is to become independent over time.
Greenland could, in theory, claim independence from Denmark and then elect to become part of the US, either by entering a "compact of free association", akin to the US' arrangement with countries like the Marshall Islands, or as a new state. The latter would not be a quick process, likely requiring a referendum in Greenland, agreements on taxation, protections of the local Inuit majority, resource ownership, and application of US federal law, as well as a Congressional majority in the US.
Meanwhile, the US already has treaty rights to pursue military and national security interests in Greenland under the 1951 US-Denmark Defense Agreement. This agreement grants the US broad permission to: (i) operate and improve existing military facilities; (ii) deploy personnel and equipment necessary for North Atlantic and Arctic defence; (iii) take all measures necessary for collective NATO defence; and (iv) construct new facilities necessary for defence (with Danish approval). Given the "working group" now established between the two countries, US presence could well increase under these existing means.
A military conquest of Greenland?
President Trump's stated preference is a "large real estate" deal to acquire the island. Leaving aside the question of whether this would be possible under Danish law and how it could be funded from a US perspective, to date the Danish and Greenlandic Governments have both made their opposition to such a deal clear.
The Trump administration has also made clear, however, that an acquisition by force is not off the table.
Sanctions: a possible UK and EU response
Although Danish Prime Minister Mette Frederiksen has signalled that an invasion would be the end of NATO, a military conquest would put EU and UK leaders in a very difficult position. Despite statements in recent days averring the EU's commitment to upholding national sovereignty and territorial integrity, it is difficult to contemplate EU countries (perhaps other than Denmark) or the UK engaging in direct military conflict against the US. Instead, sanctions could serve as a means of condemning any violation of Denmark's borders without risking military intervention.
In the UK context, two analogies may be relevant here: Crimea and Xinjiang.
Following Russia's illegal annexation of Crimea and Sevastopol in 2014, the UK imposed a prohibition on imports, infrastructure investments and sale of dual use goods or goods and technology used for oil exploration in the region. Asset freezes and travel bans were also imposed on Crimean officials and various individuals involved in providing financial, military and propaganda support for the annexation. However, whilst some figures within the Russian Government were designated, including some of those responsible for facilitating the adoption of legislation annexing Crimea and Sevastopol into the Russian Federation, there was not a wholesale sanctioning of senior Russian lawmakers as we have since seen following the 2022 invasion. President Putin himself was only designated in February 2022.
Equally, in relation to Xinjiang, the UK imposed sanctions on four Chinese officials and a Xinjiang security body in connection with Uyghur forced labour in 2021, but to date there have been no other sanctions against the Chinese state directly. The UK also maintains export controls to prevent the export of goods that may contribute to human rights abuses in the region.
Similarly narrow sanctions could be imposed preventing UK trade with or investments in Greenland, and limiting the island's access to UK technology and services which could be used to exploit its natural resources. Rather than designate President Trump or senior members of his administration, individual designations could target a US-backed Greenlandic Government or less central members of the US Government who could be seen as responsible for shaping and implementing US policy towards Greenland. This would mitigate some of the diplomatic fall-out from imposing sanctions directly against the US or President Trump, whilst signalling opposition to any violation of Denmark's sovereignty.
The EU could, in theory, impose sanctions on the US similar to those imposed on Russia following the 2014 and 2022 invasions of Ukraine. The core legal hooks would be Article 29 Treaty on European Union (TEU) (common foreign and security policy decisions), Article 215 TFEU (implementing regulation), guided by Article 21 TEU (EU external action principles) and the EU’s longstanding nonrecognition practice when a territorial change results from a violation of Article 2(4) of the UN Charter (prohibition of the use of force). In principle the EU can use emergency powers to circumvent unanimity requirements, but in the context of Greenland it appears unlikely that any sanctions would be adopted against the US in the absence of unanimity.
As with the UK, the EU would likely look to avoid sanctioning the US or the Trump administration directly. The US is Denmark’s largest export market, so even Denmark may be wary of the economic implications of direct sanctions against the US. Instead, the EU could also impose Crimea-style sanctions against a US-sponsored Greenlandic Government and its supporters. That said, the economic impact of any such sanctions may be very limited in practice – and may prompt retaliatory US tariffs – so the EU and UK may not be prepared to risk their relationship with the US over what would largely be a symbolic gesture.
In addition to sanctions, Denmark could, theoretically, call upon other EU Member States under the mutual assistance clause of Article 42(7) TEU, which applies if one Member State is the victim of armed aggression on its territory. It has, so far, only been invoked once, by the French Defence Minister in the wake of the attacks in Paris in 2015. Invoking this clause against the US, however, seems highly unlikely.
Other legal ramifications
As with Russia's invasion of Ukraine, any military or even civil intervention in Greenland could have overnight implications for supply chains, contractual obligations and prompt a widespread exit from the region. Disruptions to shipping routes or fishing waters could have wider consequences for parties operating in the North Atlantic and Arctic. We have seen in the Russia-Ukraine conflict that contractual protections like force majeure (and frustration under English law) may not always offer a justification for non-performance or a power to seek a remedy – this may be complicated further if there is ambiguity or disagreement over how to characterise US actions.
Depending on the nature of any US takeover, there would also be important questions over how companies operating in Greenland under Danish Government contracts could continue to do so, and what compensation might be available if the US were to nationalise or expropriate natural resources or assets, particularly since Greenland falls within the 1961 Friendship, Commerce, and Navigation Treaty. Any American seizure of mineral or other natural resources in Greenland that are currently owned by private companies would no doubt lead to a deluge of litigation and arbitration in the US and abroad.
Conclusion
President Trump's recent actions show that he is willing to put the so-called "Donroe Doctrine" into action. Although the administration's current focus on Greenland may be a tactic to gain greater US access to Greenland’s rare minerals and an increased US and NATO military presence in the Arctic, it remains to be seen how far President Trump would be prepared to test European and NATO allegiances. It is certainly clear that traditional alliances are shifting and recalibrating and that the post-1945 world order is being rewritten.
In the face of these changes, sanctions are likely to remain a vital weapon in countries' diplomatic arsenals, particularly in an inter-dependent globalised world where countries must navigate complex economic and political realities. However, unlike the global sanctions response to events in Ukraine, any response to a disputed shift in control in Greenland may see significant divergence in the global sanctions landscape. As demonstrated by the volume of litigation and commercial disputes precipitated by the sanctions on Russia, even where these regimes are aligned there can be significant uncertainty regarding their impact and interaction. The impact of divergent responses to Greenland would likely be significant.
Clearly the macro political and economic picture is unpredictable for 2026 and is likely to be volatile until at least the US midterm elections in November, which at the current tempo of events are a long way off. In the meantime, however, those with interests in Greenland, Denmark and the Arctic should be thinking about their exposure in the region and how robust their contractual protections would be if what was previously unthinkable were now to happen.