Is it permissible under international law for the United States to use economic leverage to force another nation into yielding territory? The answer, according to a legal expert, is quite complex.

The European Union’s agreement is now in jeopardy as members of the European Parliament have announced plans to postpone its ratification. This move comes in response to President Trump’s controversial threats involving Greenland.

The question of whether imposing tariffs on Denmark equates to illegal coercion hinges on the magnitude and economic repercussions of those tariffs, explained Rothwell.

Rothwell noted that if Denmark were to succumb to such pressure, it would raise significant doubts about the legality of any resulting treaty, due to the influence of the U.S. trade measures against Denmark.

Nonetheless, Rothwell pointed out that these arguments do not affect the core legal assessment.

Trump invokes global security as justification

Those arguments have no bearing on the legal analysis, according to Rothwell.

He said the issue was “very emotional” for the people of Greenland and Denmark.

Protesters gathered in front of the US consulate in the Greenlandic capital, Nuuk, on Saturday, bearing signs saying “Greenland is not for sale”. Source: Getty / Sean Gallup

“Ideas that would not respect [the] territorial integrity of the Kingdom of Denmark and the right of self-determination of the Greenlandic people are, of course, totally unacceptable.”

Thousands of people took to the streets in Denmark and Greenland over the weekend to protest Trump’s demands. Demonstrators bore signs reading “Greenland is not for sale”, “We are not property”, and “Our land, not yours”.

Greenlanders’ right to self-determination

A recent poll found 85 per cent of Greenlanders did not want to become part of the US, while more than half said they would vote in favour of Greenlandic independence from Denmark.

Danish foreign minister Lars Løkke Rasmussen and his Greenlandic counterpart, Vivian Motzfeldt, met with US officials on Wednesday. Source: Getty / Bloomberg

UN rights and legal experts expressed serious concerns this week about Trump’s posture, calling on the US to “unequivocally reaffirm its commitment to the UN Charter”.

Rothwell said that while there is no timeline for Greenlandic independence, it’s a realistic future possibility — meaning any attempt to acquire the territory without the endorsement of its people would breach their right to self-determination.

‘Unprecedented’ situation

“The United States is using diplomatic, political and now economic levers,” he said. “They’ve threatened military measures, but they haven’t gone that far.”

‘Worrying moment’ for global stability

From a global security and stability perspective, “this is a pretty worrying moment”, Rothwell said, with a diplomatic resolution “increasingly looking unlikely” as positions harden on both sides.