Trump’s (not so) new Arctic deal: how Denmark recycled 75-year-old diplomacy

Picture 1: "Greenland Security Agreement Ceremony"

“For over 100 years, Presidents have known the strategic importance of Greenland, but NONE of them were able to do anything about it,” posts US President Donald Trump on his own social media platform, Truth Social, on September 18th, only one day after the White House announced a deal with Denmark granting the US a permanent and larger military presence in Greenland. Further down in the post, Trump claims himself “to be the President that permanently and conclusively addressed this very important situation”. A very bold claim, is it not?

What is true about this claim is that the US indeed has had a strategic interest in the Arctic for a long time now, dating back at least to William Seward’s interest in acquiring Greenland and Alaska in 1867. It is not as black and white, however, when it comes to Trump’s framing of himself as the first president with a successful Arctic deal. The September 2026 “deal”, as Trump likes to call all of his agreements, was more like repacking an old wine in a new bottle: He and Denmark mainly re-agreed on the already existing 1951 defense agreement.

What changed is the ground on which this agreement now stands, and more precisely, how fast it is melting.

Picture 2: Arctic Shipping Routes

Currently, the Arctic is warming nearly three times faster than the rest of the world. NASA reports approximately 30 million tons of ice melting per hour in Greenland, so the area becomes a strategic interest zone for new shipping routes. A seasonally ice-free ocean is projected by 2050, opening up the Northwest Passage and Northern Sea Route to navigation and exposing new strategic resources. To the US, this translates very simply to new opportunities to generate power against other world powers. When Trump, over the last few years, repeatedly threatened to annex Greenland, it was this exact logic at play. The profound climatic changes in the High North are pushing the US’ zero-sum calculations: allowing Russia or China a foothold in the region would constitute a great relative loss in US geopolitical power. Full control of Greenland, however, would secure the GIUK Gap, a strategic maritime chokepoint in the North Atlantic, against Russia’s Northern Fleet and simultaneously deny Chinese economic access through Greenlandic mining ventures. 

And actually, Washington has run this calculation before.

America’s first Greenland bid

Exactly 80 years earlier, in 1946, the Truman administration secretly offered Denmark 100 million USD in gold for acquiring the former Danish colony, referring to the “vital importance of Greenland to US security”. While Denmark refused the offer, it led to the creation of the 1951 Defense Agreement, still granting the US extensive military base rights in designated areas across Greenland, just without formal ownership. The 1946 attempt was conducted in secret and revealed only decades later, so the US strategy was different, but the driver behind the policy also came from the outside: the Soviet Union.

Why did Greenland already matter so much to the US back then? The short answer to this question is geography. The most direct air route from the US to the USSR crossed over the Arctic Ocean and, without exception, also over Greenland. Actually very freshly established, the US National Security Council passed a secret document, informing the government that they could not imagine any war in the next decades where strategic control in Greenland „would not be of extreme importance“ for their war effort. If the Soviets were to attack, having early warning and interceptor sites on this most direct route would help the US defend its country decisively, the top priority for the US as the leader of the Western bloc in the Cold War.

This logic was not unique to just the Greenland case. Wherever the Soviets’ interest emerged, the US attempted to balance the power. Prior to 1920, another Arctic region only 500 miles away from Greenland, Spitsbergen, was determined terra nullius, a no-man’s-land, in which the US had zero military interest. However, once the Soviets began negotiating special privileges with Norway over the Spitsbergen archipelago, the US began to reconsider its own position, here meaning reassessing Greenland’s strategic value. The Soviet interest in one Arctic region was tied to American interest in another. Having established this strategic importance officially, what could possibly be the next logical step for the US to pursue that interest? Buying full control.

Soon, the Joint Chiefs of Staff had a concrete policy vision: advocating strongly for a purchase of the island in order to ultimately secure America’s strategic access. 

A cold December night, 1946, New York City: Secretary of State James Byrnes meets with Danish Foreign Minister Gustav Rasmussen and proposes three outlined solutions for Greenland’s future defense, alongside 100 million USD paid in gold. However, Rasmussen did not react favorably to the idea of granting the US either the rights to construct and maintain bases in specified areas, a bilateral defense treaty, or what Byrnes framed as “possibly the best solution, in the long run, both from the Danish and US points of view”: the outright purchase. The only thing Rasmussen promised was to sleep on it, before making a final decision. 

Half a year later, a secret Danish telegram reached Washington. The message: “There was no possibility of sale of Greenland”. Rumors also reached Moscow and the press started circulating, leading the Soviet ambassador in Copenhagen to inquire whether the US offer really was considered. In response, Rasmussen himself called the idea “absurd”.

But the US did not give up.

Plan B: Presence instead of Purchase

The Soviets’ First Lightning operation in 1949 struck with consequence: a successful nuclear test in the Kazakh Soviet Socialist Republic (modern-day Kazakhstan) was followed by the outbreak of the Korean War and the increasingly perceived necessity to arm up against communism. A typical Cold War containment logic at play. Measures had to be taken, so Secretary of the Air Force Thomas Finletter started studying potential strategic areas. Where could the US counterbalance its power? 

Picture 3: Thule Air Base, National Security Archive

Finletter calculated that the northwestern coast of Greenland, a place called Thule, was the most viable location, able to reach 85% of all Soviet targets. Construction of a Base started in 1951. In spring of the same year, the US and Denmark signed a new defense agreement, five years after the rejected offer from the New York winter meeting. A purchase was still off the table, but the content of the agreement came shockingly close: without any compensation, the US was entitled to extensive operational rights at Thule and other designated defense areas as well as “control landings, takeoffs, anchorages, moorings, movements, and operation of ships, aircraft, and water-borne craft and vehicles […]” (Art. II (3)). Additionally, Washington negotiated exclusive jurisdiction in these specific areas (Art. VIII). This agreement was concluded to stay in effect as long as NATO would persist. It persisted when Trump first expressed his interest in buying Greenland in 2019 and even when he did not rule out military force in taking control of the area.

And then: Nothing.

No purchase, no military attack to gain full strategic access to Greenland.

So what did Trump actually get in September that made him so confident about his Arctic success? Ultimately, they were amending this exact 1951 agreement, and it has to be said, very minorly so. From now on, all 3 parties must sign their consent when a non-NATO member wants to build a military presence or invest in critical sectors and secure these amendments even in the case of an independent Greenland. This might take away some of Trump feeling threatened by China or Russia, but ultimately is not as victorious as Trump likes to portray it on social media. 

"Don't tell Trump that it's the Kingdom of Denmark that has won," is also what Jacob Heinel Jensen, US correspondent of the Danish newspaper ‘Berlingske,’ reports. 

Overall, it seems Denmark had enough of Trump’s repeated threats and decided to change its strategy on the whole matter. Taking the essence of the existing deal and wrapping it in a new gift wrap, with a lovely new bow, and presenting it as a great present Trump earned himself as “the first president” ever, proved to be exactly what would get him to calm down about the situation. Well played, Denmark.