Could Trump Leverage Tariffs to Secure a Greenland Deal? Exploring the Legalities and Implications

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United States President Donald Trump has escalated his longstanding designs on controlling Greenland, vowing to levy higher tariffs on European allies until the United States is allowed the “complete and total purchase” of the autonomous Danish territory.

The tariffs would be “payable until such time as a deal is reached for the complete and total purchase of Greenland”, Trump added.

The countries Trump singled out — all of which already face tariffs imposed by the US president last year — have pledged support for Denmark and the people of Greenland.

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.

Donald Rothwell, a professor of international law at the Australian National University, said the legality of each tariff would depend on the individual trade agreements the US has with each European country.

The trade law implications are “quite significant”, he said, given the transatlantic trade deals the White House reached last year with the European Union and United Kingdom.

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.

Leaders in both Denmark and Greenland, a mineral-rich Arctic territory of strategic importance to the US, have repeatedly said the island is not for sale.

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.

“We’re not at that point at the moment,” he told SBS News. “But in theory, if State A was to impose absolutely crippling tariffs on State B, well, then that would certainly raise some international questions.”

However, if Trump does manage to extract a treaty agreement from Denmark to cede Greenland to the US, its validity could be murky.

“Any treaty concessions by one state to another forced upon a state as a result of coercive activity undermine the legitimacy of the treaty arrangement,” Rothwell explained.

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

Trump invokes global security as justification

Trump has said he is acting in the interests of global and national security, writing in his Truth Social post that “China and Russia want Greenland” and that “world peace is at stake”.

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

Trump has not ruled out using military force to take Greenland, though the White House says he prefers diplomacy.

The foreign ministers of Denmark and Greenland met with US secretary of state Marco Rubio and vice president JD Vance this week but were unsuccessful in shifting the US position.

“It’s clear that the president has this wish of conquering over Greenland. And we made it very, very clear that this is not in the interest of the kingdom,” Danish foreign minister Lars Løkke Rasmussen told reporters afterwards.

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

Protesters carry red and white flags and signs saying "Greenland is not for sale" in a snowy area.

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

Under the United Nations Charter, the people of Greenland have a recognised 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.

A man in a black jacket, blue shirt and blue tie, walking alongside a woman wearing a dark grey blazer and black top.

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 UN Charter came into force in October 1945, after the end of World War Two.

In the 19th and early 20th centuries, it was not uncommon for major powers to acquire territory in pursuit of national interests. However, in the post-1945 world order, Rothwell said, such conduct by the US is “unprecedented”.

He drew broad parallels between the US’ current moves and Russia’s approach in the lead-up to its 2022 invasion of Ukraine, noting the gradual escalation of pressure.

“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.

If the US fails to achieve its objectives through economic pressure and continues on its current trajectory, it may ultimately resort to military force to take Greenland — a move that would, in Rothwell’s view, trigger the immediate collapse of NATO.

Denmark’s Prime Minister, Mette Frederiksen, has also indicated that a military takeover of Greenland by the US would mark the end of the military alliance.

“Once NATO collapses,” Rothwell said, “the global security environment is going to be reshaped.”