The American president's demand for control over Greenland violates international law, international agreements and the constitution. This is the conclusion of a new study from the Faculty of Law.
Imagine that an allied superpower publicly declares that your country should change ownership - and that military force cannot be ruled out. It sounds like a bad Hollywood film, but last winter it became reality for Greenland and Denmark. A reality that has been reignited in early 2026, when the US president once again stated that Denmark's close ally across the Atlantic must have Greenland.
When Donald Trump, at the start of his second term as president, reinforced the demand he originally made in 2019, he created a foreign policy crisis that calls into question both sovereignty and constitutional principles. Now, new research explains why the case is not only sensational, but also a so-called diplomatic extreme.
'A diplomatic extreme is a public diplomatic act that is so far-reaching that it challenges fundamental legal and political rules. Furthermore, it unfolds on social media, making it visible and within everyone's reach,' says Mette Marie Stæhr Harder, assistant professor at the Faculty of Law.
Together with Professor Helle Krunke, she is author of the study, which has been published in the scientific journal Constitutional Studies.
'The American demands respect neither the Danish constitution nor international law and agreements. It is rhetoric that breaks with the whole idea of constitutional and international legal order - a diplomatic extreme,' states Helle Krunke.
Security, fear and social media
The two researchers emphasise that even though Greenland is part of the Danish realm according to international agreements and the constitution, the US is casting doubt on Denmark's authority in the matter and making undefined threats.
- What is happening? In the winter of 2024-2025, President Trump once again declared that the United States should control Greenland - and he would not rule out military force as an option.
- Why is this extreme? The statements violated the Danish Constitution and international law and agreements, including NATO cooperation. Furthermore, the statement was accessible to everyone - via social media, it entered the private sphere of both Greenlanders and Danes.
- How have Denmark and Greenland reacted? Both governments have portrayed the situation as a threat, but with different areas of focus.
- Has Greenland tried to gain more foreign policy power? No - despite a history of Greenland continuously seeking to expand its foreign policy role when the opportunity arose, Greenland has stuck to the existing division of powers in this case.
'When you look at the existing agreements, the argument that the US "needs" control over Greenland for the sake of its national security is completely untenable. The United States can safeguard its security interests within the framework of its defence agreements with Denmark and Greenland,' emphasises Helle Krunke.
The study also maps out how Danish and Greenlandic politicians have expressed themselves on the matter so far. The researchers have analysed posts on social media by Greenlandic and Danish ministers. Both sides have portrayed the situation as a threat - but from different angles.
'Danish leaders have spoken of a threat to the Realm and international norms, while Greenlandic leaders have focused on the fear of internal division,' explains Mette Marie Stæhr Harder.
The tone on social media has been dramatic: 'We are not for sale,' wrote Greenland's then Prime Minister Múte B. Egede last winter, while Prime Minister Mette Frederiksen spoke of 'a new, dangerous era'. The population followed suit: an opinion poll showed that 85% of Greenlanders rejected any idea of becoming part of the United States.
Why did Greenland not take advantage of the situation?
One might think that Greenland would use the crisis to strengthen its foreign policy role. But the study shows the opposite:
'Despite a history of gradually expanding its powers, we see no signs that Greenland is attempting to expand its foreign policy power during the crisis,' says Mette Marie Stæhr Harder, elaborating:
'On the contrary, Greenland has apparently taken a step back from its declared principle of "Nothing about us without us" - that nothing should be decided about the country without its involvement.'
She refers to the fact that Greenlandic leaders allowed Denmark to take the initiative in international negotiations in early 2025.
'When the Danish Prime Minister publicly emphasises that Greenland's future will be decided in Nuuk, it sends a strong signal of respect. This may have created goodwill and reduced the need to push for more influence,' concludes Mette Marie Stæhr Harder.
The study is entitled 'Diplomatic Extremes and Constitutionalism: The Case of the United States, Greenland, and Denmark'. Read it here (the study begins on page 357 of the journal).
