Introduction

On 18 September 2026, US President Donald Trump announced that the US had reached an agreement with Greenland, which would enable the US to expand its military presence in Greenland, the world's largest island. This follows months of negotiations and several attempts from the Trump administration to increase US control over Greenland, which included the suggestions of outright purchase, a Compact of Free Association, or expanding US military presence using a 1951 treaty between the US and Denmark. In January 2026, President Trump even raised the possibility of taking over the island through military force, alarming Greenlanders and sparking a backlash from European leaders as well as Republican lawmakers in the US.

Potential reasons for increased US presence

US national security

President Trump has primarily framed his pursuit of Greenland in the context of US national security. He argued that the island is under threat from Russia and China, and that Denmark cannot secure it from these dangers. Commentators describe Greenland's geographic position as a critical piece of Trump's 'Golden Dome for America' missile‑defence architecture – particularly given the hypersonic and cruise missile possibilities showcased by Russia and China. The island is also important for military training purposes, as the recent (7‑18 September 2026) Arctic Shield NATO exercise highlighted. Greenland provides a unique terrain (low population, limited transport infrastructure, mountainous terrain and challenging meteorological conditions) for testing logistics and drone operations. Others, however, questioned this rationale, highlighting the fact that, when US military leaders explored acquiring Greenland in the 1950s, the State Department concluded that the US already had the ability to carry out a wide range of military activities there, without compromising its relationship with Denmark or Greenland. This is still the case today. Moreover, commentators note that while the US maintained 17 military installations and more than 10 000 personnel in Greenland during the Cold War, it only keeps around 150 military personnel in its Pituffik (formerly Thule) ⁠Space ​Base in northwest Greenland.

Critical minerals

Other experts explain that the US president's and administration's actions were motivated by the island's mineral reserves. They note that, back in 2019, during Trump's first term, the US and Greenland had signed a memorandum of understanding to jointly survey the region and exchange scientific and technical knowledge to develop rare earth and critical mineral resources. Greenland is rich in natural resources; including iron ore, graphite, tungsten, palladium, vanadium, zinc, gold, uranium, copper, and oil. However, the resources attracting the most attention to the region are rare earth elements (REEs), especially following China's 2025 export controls on REEs. Indeed, Greenland ranks eighth in the world for REE reserves, with 1.5 million tons, and two rare earths deposits (Kvanefjeld and Tanbreez) that are among the largest in the world. The Tanbreez site is estimated to contain potentially the world's largest deposit of REEs, at 28.2 million metric tons, over 27 % of which is estimated to consist of heavy rare earths. Moreover, tantalum, niobium, and zirconium can also be found there. Kvanefjeld is the third‑largest known land deposit of REEs, with over 11 million metric tons of reserves and resources, including 370 000 metric tons of heavy rare earths. Furthermore, the deposit also contains 270 000 tons of uranium, making it the eighth‑largest uranium deposit in the world. In this regard, Greenland is part of the US's multi‑faceted diversification strategy, which also involves Saudi Arabia, Japan, and Australia.

In June 2025, the US Export‑Import Bank sent a letter of interest to the Critical Metals Corp offering a US$120 million loan to fund the company's Tanbreez rare earth mine in Greenland. Commentators note that, if approved, the loan would be the Trump administration's first overseas investment in a mining project. They also observe, however, that no rare earth mining has taken place on the island to date, due to the harsh Arctic climate, which prevents mining activities on most of Greenland throughout much of the calendar year. In the same way that warming global temperatures may increase the mining potential on the island, increasing investment could also achieve this.

Despite their potential, these REE projects are not void of difficulties. For example, the development of the Kvanefjeld rare earth mine has been blocked, because the Inuit Ataqatigiit Party, which won Greenland's parliamentary elections in 2021, passed legislation banning exploration and mining of mineral deposits with a uranium concentration of over 100 parts per million. This is to protect the environment, public health, and Greenland's tourism and fishing industries (the uranium concentration in Kvanefjeld is around 300 parts per million). As a result of the uranium mining ban, the Kvanefjeld project has been tied up in litigation since 2022. The company Energy Transition Minerals argues that the legislation constitutes expropriation and demands compensation of US$11.5 billion, equivalent to nearly four times Greenland's GDP as of 2023.

Experts note that, in addition, further development of Greenland's mining sector is impeded by inadequate transport and energy infrastructure. The entire island, larger than France, Spain, Germany and the United Kingdom (UK) combined, has only 93 miles of road. Furthermore, Greenland has only 16 ports, each with limited capacity. The Nuuk port, the island's largest, carried 2 million tons of cargo in 2021. The closest large port near the Kvanefjeld and Tanbreez mines is the Narsaq port, which handles only 50 000 tons of cargo annually – in comparison, Rotterdam's port carries 428 million tonnes of freight every year, while Antwerp/Bruges' port carries around 270‑280 million tons. Additionally, electricity generation is inconsistent and limited. The largest installed electricity generation capacity is currently 54 megawatts in the capital city of Nuuk, 290 miles away from Narsaq. Significant investment in energy transmission and capacity will be a necessity for any mining operation.

Beyond hoping to exploit these deposits in the future itself – notwithstanding the inherent difficulties and necessary investment – experts remarked that the US also wants to prevent other countries from exploiting the deposits. Specifically, China's continued interest in Greenland and a 2025 statement by Greenland's minister of business and mineral resources – that while the country prefers western partnerships, it would not hesitate to turn to other countries (including China) if no investments materialise – gives credibility to this argument.

A legal way to transfer sovereignty

Other experts have focused not on the reasons behind, but on the implementation of the 2026 US–Denmark–Greenland agreement. They explored the claims of President Trump that he wanted to purchase Greenland. They noted, in this context, that, contrary to cases in the past (such as the states of. Alaska and Louisiana), Denmark cannot 'sell' Greenland to the US if the locals object; as it would be in breach of both international law and Greenland's self‑determination act. Experts speculated, therefore, whether the solution could be, as reported by the press back in January 2026, for instance, to transfer a sovereign title to one or more military base areas in Greenland, as is the case with the UK's sovereign base territories in Cyprus. They commented that, unlike the UK's base in Cyprus, most other international basing agreements see the host country retain sovereignty over the territory on which a base is located, only agreeing not to exercise its own jurisdiction, instead allowing the foreign state to apply its own. In addition, the Danish Parliament would have to approve such a transfer of sovereignty – and even if it did, if Greenland gained independence, that could create legal issues for the US, as was the case with the Chagos islands. That is to say, Greenland would be able to claim that the transfer of sovereignty had taken place without its valid consent (as it was Denmark that agreed to it). To avoid such legal complications and ensure continued access to the island, experts concluded that the treaty could simply confirm that the existing base arrangements are permanent and will be inherited by Greenland, should it ever become independent.

The agreement

The agreement between the governments of the US and Denmark, together with the government of Greenland 'to amend and supplement' the 1951 agreement and all subsequent relevant agreements, focuses on three main areas: (i) military bases ('defence areas), (ii) foreign investment and (iii) the state of play if Greenland becomes independent.

Regarding military bases, the agreement allows the US to modernise and expand its activities in the Pituffik Space Base and to establish additional military bases at Narsarsuaq and Mestersvig, and gives it the right to establish additional defence areas and strengthen its military operations or facilities in the future. It also gives the US right of movement by land, air and sea through Greenland between its defence areas; and access to the island's territorial waters for its vessels and submarines. According to the agreement, no other state which is not a member of NATO will be allowed to establish military installations or military forces on the island. In addition, the territories in the vicinities of the military bases will not be used in any way that could threaten the security of the bases. The parties will also cooperate to counter espionage.

On foreign investment, the agreement establishes that investors from a state that is not a member of NATO, a NATO partner, or an EU Member State will not be allowed to have control, significant influence, or access to non‑public information that may constitute a threat to national security or public order within Particularly Sensitive Sectors or Activities in the territory of Greenland – including territorial waters. These sectors' activities include, but are not limited to, critical infrastructure and resource extraction.

If Greenland exercises its right to self‑determination to become independent, the agreement provides that the Danish Government and the Government of Greenland will have to ensure together that the independent Greenlandic state will agree to remain in NATO, and assume all the rights and obligations to the Kingdom of Denmark specified in the agreement.

Lastly, the agreement deletes the provision in the 1951 agreement which linked the duration of the agreement to the duration of NATO, and establishes that the new agreement has no specific end date and can only be amended by mutual consent.

Reactions

The agreement was welcomed by all three parties principally involved. In addition, European Council President António Costa and European Commission President Ursula von der Leyen both welcomed the agreement.

Experts are of the view that the agreement serves both domestic and international goals for the US. Domestically, the agreement, which comes weeks before the midterm elections, serves as a foreign policy accomplishment by the administration, in contrast to the unpopular Iran war. It will also help the US strengthen its military posture on the island and constitutes a further step for the president's Golden Dome initiative. Additionally, the ability to uphold the agreement in the event of Greenland's independence, coupled with preventing China from making significant investments or installing troops in Greenland, greatly reduces the possibility of geopolitical realignment of the island. Finally, complemented by international investments, it will help US companies to further harness the island's resources and the country to exert more influence on the island than solely through the military.

As far as Denmark is concerned, experts praised it for extricating itself from a period of coercive US diplomacy over Greenland, without significant concessions and with reinforced national feelings. They noted the agreement reaffirms the sovereignty and territorial integrity of Denmark and acknowledges Greenland's right to self‑determination.By denying would‑be secessionist parties in Greenland the possibility of promising to expel the US military presence from Greenland (or to invite large new investments from China or other excluded nations), the agreement undermines – at least part of – the political and economic case for a future independent Greenlandic state.