US Greenland Deal: Does America Now Control Greenland?
Introduction
The US Greenland deal announced on September 18, 2026, does not transfer sovereignty over Greenland to the United States. President Donald Trump described the arrangement as granting Washington permanent authority over the island’s security, including expanded military access and restrictions on activities by American adversaries. Denmark’s Prime Minister, Mette Frederiksen, affirmed that the agreement recognizes the sovereignty and territorial integrity of the Kingdom of Denmark and the Greenlandic people’s right to self-determination. Greenland’s Prime Minister, Jens-Frederik Nielsen, welcomed the agreement as a means of strengthening regional security while recognizing Greenland’s interests in international cooperation (Slattery et al., 2026; Prime Minister’s Office of Denmark, 2026).
American military access to Greenland predates the new arrangement by more than seven decades. The 1951 Defense of Greenland Agreement established extensive rights concerning military facilities and operations within agreed defense areas, while preserving Danish sovereignty. Its 2004 amendment further regulated military activities and consultation with Danish and Greenlandic authorities. The September 2026 agreement must consequently be understood in relation to these existing rights. Its legal significance depends on the additional authority it grants Washington and how that authority is exercised within territory that remains part of the Kingdom of Denmark (United States and Denmark, 1951, 2004).
The agreement also concerns the wider security of the Arctic and North Atlantic. Trump has announced plans to expand the American military presence and restrict adversaries from establishing bases or making sensitive investments in Greenland. Reuters reports that additional provisions would restrict military installations by non-NATO countries, although the precise scope of these restrictions remains unclear (Slattery et al., 2026). The three governments expect to sign the agreement during the United Nations General Assembly, with entry into force subject to the necessary national parliamentary procedures. Until its full terms are available and those procedures are completed, the extent of any new American security powers cannot be established conclusively (Prime Minister’s Office of Denmark, 2026).
1. What Does the US Greenland Deal Actually Provide?
The US Greenland deal announced on September 18, 2026, concerns an expanded American military presence and restrictions on certain foreign activities in Greenland. President Donald Trump announced that negotiations with Denmark and Greenland had produced an arrangement securing long-term American defense access. He described the outcome as giving Washington permanent authority to meet its security requirements on the island, although the agreement does not transfer Greenland to the United States (Slattery et al., 2026).
Trump stated that the United States would develop a substantial military presence in Greenland. He also declared that American adversaries would be prevented from establishing military bases or maintaining a military presence without US approval. According to his announcement, sensitive investments by those states would require express written American authorization, and the arrangement would have no expiration date. These claims establish Washington’s stated objectives, but the precise geographical and operational scope of the proposed rights has not been publicly established (Slattery et al., 2026).
Denmark and Greenland described the agreement in terms of collective security rather than a transfer of governmental authority. In a September 18 statement, Danish Prime Minister Mette Frederiksen said the arrangement would strengthen security in the Arctic and North Atlantic while recognizing the sovereignty and territorial integrity of the Kingdom of Denmark and the Greenlandic people’s right to self-determination. Greenlandic Prime Minister Jens-Frederik Nielsen emphasized that the agreement recognizes Greenland’s interests and its place in international cooperation. Neither statement provides a detailed account of the additional military powers Washington would acquire (Prime Minister’s Office of Denmark, 2026).
Additional information emerged from American officials. Secretary of State Marco Rubio stated that the agreement addressed Washington’s long-term national security concerns and would keep Greenland within North America’s strategic defense area. An anonymous State Department official told Reuters that the arrangement would prohibit non-NATO countries from establishing military bases in Greenland and restrict unspecified sensitive investments to the United States and its allies. The official also described permanent American access, basing, and overflight rights. These reported provisions have not yet been confirmed against the agreement’s complete operative text (Slattery et al., 2026).
The distinction between these accounts is legally significant. Trump’s reference to American adversaries does not necessarily establish the same restrictions as a prohibition applying to every non-NATO country. Likewise, an investment restriction may concern particular sectors, transactions, or national security interests without extending to Greenland’s entire economy. The available statements do not establish the applicable definitions, geographical limits, approval procedures, or exceptions. They also leave unresolved whether the United States would need further Danish or Greenlandic agreement before establishing additional defense areas.
The arrangement has not completed the procedures necessary for entry into force. Denmark’s Prime Minister’s Office announced that the three governments expect to sign it during the upcoming United Nations General Assembly and that the necessary national parliamentary procedures must follow. The announcement establishes an agreement in principle, but it does not demonstrate that the reported new rights are already legally operative. Existing American military activities continue to have their legal basis in the defense arrangements previously concluded with Denmark (Prime Minister’s Office of Denmark, 2026; United States and Denmark, 1951, 2004).
2. Does the Agreement Give America Control Over Greenland?
Greenland remains a self-governing part of the Kingdom of Denmark. Under the 2009 Act on Greenland Self-Government, Greenlandic authorities exercise legislative and executive powers in fields of responsibility that have been transferred to them. Foreign and security policy remain matters for the Kingdom, although the legislation establishes arrangements for Greenlandic participation in international affairs affecting its interests (Denmark, 2009, ss. 1, 11–13).
The expression American control can describe several legally different relationships. Washington may exercise operational authority over military installations, enjoy extensive rights of access, or participate in decisions concerning Greenland’s external security. None of those powers necessarily gives the United States territorial sovereignty or replaces the civilian institutions responsible for governing Greenland. The 1951 Defense Agreement expressly preserves Danish sovereignty while permitting American authorities to exercise substantial powers within agreed defense areas (United States and Denmark, 1951, art. II).
The announced deal could nevertheless affect the practical distribution of security authority. Restrictions on third-country military activities and sensitive investments, if implemented as reported, would give Washington a more direct role in decisions extending beyond the daily operation of its existing military facilities. The extent of that role depends on the agreement’s precise provisions and their relationship with Danish and Greenlandic powers (Slattery et al., 2026).
Denmark’s express affirmation of its continuing sovereignty establishes the participating governments’ stated territorial position. It does not, however, resolve every question concerning the exercise of authority under the proposed arrangement. The distinction between sovereignty and security control allows American military influence to expand without changing Greenland’s territorial status, but the allocation of particular powers remains a separate legal question (Prime Minister’s Office of Denmark, 2026).
2.1 Sovereignty and Foreign Military Authority
Territorial sovereignty concerns a state’s legal authority over its territory, including the exercise of governmental jurisdiction and its position in international relations. A state may consent to the presence of foreign armed forces and grant them defined operational powers without surrendering that sovereignty. Such arrangements are governed by the relevant international agreements, which determine the activities authorized, the responsibilities allocated to each government, and the geographical limits of foreign military operations.
The 1951 Defense Agreement illustrates this distinction. Article II provides for defense areas selected by agreement between the United States and Denmark. Where the United States assumes responsibility for operating an agreed area, it may construct military facilities, station personnel, and provide for the area’s protection and internal security. The same provision expressly preserves the Kingdom of Denmark’s sovereignty over the defense area and recognizes the competent Danish authorities’ right of movement throughout Greenland (United States and Denmark, 1951, art. II).
Operational command must also be distinguished from territorial jurisdiction. Command concerns the direction of military personnel and operations, whereas jurisdiction concerns the authority to prescribe, apply, and enforce legal rules. A defense agreement may allocate particular responsibilities to the foreign military while leaving other matters within the territorial state’s legal system. The legal position of military personnel can also be governed by a separate status-of-forces agreement.
In Greenland, the NATO Status of Forces Agreement provides the principal framework for the relevant criminal jurisdiction arrangements. Article VII addresses the allocation of criminal and disciplinary jurisdiction between the sending and receiving states, including circumstances in which both may exercise jurisdiction. The application of that framework in Greenland was expressly confirmed by the 2004 amendment to the Defense Agreement (NATO, 1951, art. VII; United States and Denmark, 2004, art. 2).
Greenland’s constitutional position introduces a further division of authority. Naalakkersuisut, the Greenlandic government, and Inatsisartut, the Greenlandic parliament, exercise powers within Greenland’s fields of self-government. Danish authorities retain responsibility for matters reserved to the Kingdom, including defense and security policy (Denmark, 2009, ss. 1 and 11).
American military privileges operate within the applicable legal arrangements governing those responsibilities. They cannot automatically be interpreted as authority over Greenland’s civilian administration, natural resources, or domestic legislation. Particular defense or investment restrictions may nevertheless affect activities within Greenland’s transferred fields of responsibility. Their legal consequences depend on the powers actually granted and the domestic arrangements governing their implementation.
2.2 What Does Permanent Security Control Mean?
Trump’s description of permanent American security control raises a question about the duration and legal character of the reported rights. Reuters reports that the agreement has no expiration date and that an American official described its access, basing, and overflight rights as permanent. Those statements indicate an intention to establish an enduring security relationship. They do not, by themselves, establish that the rights are irrevocable or that Washington has acquired unlimited authority over Greenland (Slattery et al., 2026).
An agreement concluded for an indefinite period is not necessarily incapable of amendment or termination. The legal position depends primarily on the agreement’s own provisions, the consent of the parties, and any other applicable rules of international law. A distinction must also be drawn between a treaty that can be amended by agreement and one that permits a party to withdraw unilaterally.
Articles 54 and 56 of the 1969 Vienna Convention on the Law of Treaties illustrate the importance of these distinctions. Article 54 addresses termination in accordance with a treaty’s provisions or by consent of all parties. Article 56 sets restrictive conditions for denunciation or withdrawal where a treaty contains no relevant provision. The absence of an expiration date alone does not establish a unilateral right to terminate an agreement (United Nations, 1969, arts 54 and 56).
The Convention is not, however, directly binding on the United States as a treaty. Washington signed it in 1970 but has not ratified it. The United States recognizes many of its provisions as reflecting customary international law, although the customary status and application of particular rules must be established independently. Articles 54 and 56 cannot simply be treated as treaty obligations binding the United States (US Department of State, n.d.).
Greenland’s existing defense arrangements provide a more direct illustration of how duration and amendment rights can operate. The 1951 agreement links its duration to that of the North Atlantic Treaty and permits modification by mutual consent. Its 2004 amendment remains in force for the duration of the original agreement and may also be amended by mutual agreement (United States and Denmark, 1951, arts XIII–XIV; 2004, art. 4).
The September 2026 arrangement cannot be described as creating legally irreversible American control merely because its reported terms contain no expiration date. Its durability will depend on its final provisions, including any rules on amendment and termination, and its relationship with the existing defense agreements.
3. The 1951 Defense Agreement and Existing American Rights
The legal foundation of the American military presence in Greenland predates the September 2026 announcement by more than seven decades. On April 27, 1951, the United States and Denmark concluded the Agreement Concerning the Defense of Greenland in implementation of the North Atlantic Treaty. It entered into force on June 8, 1951, following notification of Danish parliamentary approval. The agreement established a bilateral framework through which American forces could assist Denmark in defending Greenland and the wider North Atlantic Treaty area (United States and Denmark, 1951).
Article II provides for the establishment and operation of defense areas agreed upon by the two governments on the basis of NATO defense plans. The provision concerns areas considered necessary for the defense of Greenland and the wider North Atlantic Treaty area that Denmark is unable to establish and operate independently. Responsibility for operating and maintaining each selected area is determined by agreement between the governments (United States and Denmark, 1951, art. II).
Where the United States assumes operational responsibility, Article II grants extensive rights within the designated area and adjacent airspace and waters. These include developing military infrastructure, maintaining equipment, stationing personnel, storing supplies, and protecting the installation. American authorities may also regulate specified movements and activities involving ships, aircraft, and vehicles, subject to the agreement’s qualifications concerning Danish responsibilities for shipping and aviation.
American access rights extend beyond individual installations. Article V(3) provides for the movement of American public vessels, aircraft, armed forces, and vehicles between defense areas through Greenland, including movement by land, sea, and air. These rights operate in accordance with general rules mutually agreed upon and issued by the appropriate Danish authority. The provision also permits American aircraft to fly over and land in Greenland, subject to restrictions mutually agreed upon by the governments (United States and Denmark, 1951, art. V(3)).
These rights were accompanied by safeguards preserving Danish sovereignty and maintaining bilateral oversight. Article II expressly protects the Kingdom’s sovereignty over American-operated defense areas. Article XIII establishes diplomatic procedures for addressing questions of interpretation and provides for reviewing the agreement in light of experience or changes to NATO plans. Any modifications require mutual consent. The agreement also specifies that it does not alter existing command relationships (United States and Denmark, 1951, arts II and XIII).
The agreement’s duration is addressed separately in Article XIV, which provides that it remains in effect for the duration of the North Atlantic Treaty. This established framework demonstrates that extensive American military access and continuing defense commitments were already features of Greenland’s security arrangements before September 2026. The new agreement’s legal significance depends on the additional authority it grants or the changes it introduces to existing procedures, rather than the mere continuation of American military operations.
3.1 The 2004 Amendment and Its Continuing Significance
The defense relationship was further developed on August 6, 2004, when the United States and the Kingdom of Denmark, including Greenland’s then Home Rule Government, concluded an agreement at Igaliku amending and supplementing the 1951 framework. The amendment entered into force on the date of signature. It reflected Greenland’s changed constitutional position since 1951 and formalized additional arrangements for consultation and cooperation concerning American military activities (United States and Denmark, 2004).
Article 1 identified Thule Air Base, subsequently renamed Pituffik Space Base, as Greenland’s only defense area at the time of the amendment. It expressly retained Article II of the 1951 agreement as the applicable framework for establishing additional defense areas. The provision also required the flags of Denmark, Greenland, and the United States to fly over the installation and addressed cooperation between American, Danish, and Greenlandic authorities concerning its protection and internal security (United States and Denmark, 2004, art. 1).
The amendment clarified the legal position of American forces by confirming that the NATO Status of Forces Agreement had applied in Greenland since 1955. Article 2 superseded the original Defense Agreement’s Article VIII with the corresponding NATO SOFA provisions, making the latter the principal framework for the relevant criminal jurisdiction arrangements. Articles VII and IX of the 1951 agreement continued to apply as supplementary arrangements concerning taxation, customs, and the admission and departure of personnel (United States and Denmark, 2004, art. 2).
The distinction is significant because the original 1951 agreement granted extensive American jurisdiction over certain defense areas and personnel. The 2004 amendment expressly replaced that jurisdictional provision with the corresponding NATO SOFA rules. The allocation of jurisdiction must consequently be determined through the amended legal framework rather than through the superseded Article VIII.
Greenlandic participation was particularly important in the provisions concerning local cooperation. Article 3 requires the United States to consult and inform the Kingdom of Denmark, including Greenland’s Home Rule Government, before implementing significant changes to American military operations or facilities. It also addresses exceptional planned military aircraft landings outside airports, requiring consultation and notification to protect Greenland’s environment and hunting areas (United States and Denmark, 2004, art. 3).
The same article allows Greenland’s Home Rule Government to appoint a representative to consult with the American commander on local affairs affecting Greenlandic authorities. Questions concerning the American military presence must be addressed through consultation without undue delay. Issues that cannot be resolved locally may be referred to the Permanent Committee or handled through diplomatic channels. These provisions establish mechanisms for participation and consultation, although they do not confer a general Greenlandic veto over every operational decision.
The September 2026 agreement must be assessed against these established obligations. Reuters reported that it remained unclear whether the new arrangement would result in additional American bases. Under the existing framework, the establishment of new defense areas requires agreement between the United States and Denmark under Article II of the 1951 agreement, while the 2004 amendment provides for consultation with Greenlandic authorities before significant changes to American military operations or facilities.
The reported announcement does not establish that Washington has acquired an independent right to construct new bases without Danish agreement or that the existing consultation arrangements have been displaced. Those questions depend on the new agreement’s operative provisions and their relationship with the earlier instruments (United States and Denmark, 1951, art. II; 2004, arts 1 and 3; Slattery et al., 2026).
4. The Restrictions on Foreign Bases and Sensitive Investments
The reported restrictions on foreign military activity and sensitive investments are among the most consequential elements of the US Greenland deal. On September 18, 2026, President Donald Trump announced that American adversaries would be unable to establish military bases, maintain a military presence, or make sensitive investments in Greenland without express written approval from Washington. These statements describe the authority the United States expects to obtain; they do not establish that the proposed restrictions have entered into force (Slattery et al., 2026).
The scope of the restrictions differs between the publicly reported accounts. Trump referred to American adversaries, whereas an anonymous State Department official told Reuters that the agreement would prohibit non-NATO countries from establishing military bases and reserve unspecified sensitive investments for the United States and its allies. The categories are not interchangeable. A state may be outside NATO without being designated an American adversary, while the term sensitive investments has not been defined in the available statements (Slattery et al., 2026).
Military installations and commercial investments involve different governmental responsibilities. Defense and security policy remain matters for the Kingdom of Denmark, while Greenland exercises legislative and executive authority in fields transferred to its self-government institutions. An agreement addressing both foreign bases and investment decisions would need to operate within this distribution of powers. Its precise effects on Danish and Greenlandic decision-making cannot be determined from the announcement alone (Denmark, 2009, ss. 1 and 11–13).
Mineral resources illustrate the significance of that distinction. Greenland assumed responsibility for the mineral resource sector on January 1, 2010, acquiring regulatory authority over activities involving its mineral and hydrocarbon resources. A restriction concerning investment in strategically significant mineral projects could consequently affect an economic field administered by Greenlandic authorities, even if the restriction were justified by the participating governments on national security grounds (Prime Minister’s Office of Denmark, n.d.).
Greenland’s economic relationships are not confined to the United States. On September 7, 2026, the European Commission announced a €200 million Global Gateway partnership package for investments in and with Greenland during 2026 and 2027. Its stated priorities include connectivity, energy, critical raw materials, housing, and local economic development. The package demonstrates the breadth of Greenland’s international economic cooperation; its announcement does not mean that the full amount has already been disbursed or that any of these investments falls within the proposed American restrictions (European Commission, 2026).
American interest in the ownership of Greenlandic mineral projects also predates the September agreement. In January 2025, Reuters reported that Greg Barnes, the chief executive of Tanbreez Mining, said American and Danish officials had urged the company not to sell its rare-earth project to Chinese-linked buyers. The account was attributed to Barnes, and the governments concerned did not independently confirm its details in that report. It illustrates the strategic importance attached to mineral ownership without establishing that the new agreement prohibits any particular Chinese transaction (Burton and Scheyder, 2025).
The legal implications of an American approval requirement would depend on how the obligation is formulated. The participating governments might agree to consult Washington before specified decisions, make particular authorizations conditional on American consent, or undertake to prevent defined activities. Each arrangement would have different consequences for the authority of Danish and Greenlandic institutions. The published accounts do not identify the investment categories, approval procedures, exceptions, or enforcement measures.
An agreement between the United States and the Kingdom of Denmark would not, merely by its conclusion, impose treaty obligations on China, Russia, or other third states. The established principle that treaties do not create obligations for third states without their consent remains distinct from the participating governments’ ability to regulate access to territory under their jurisdiction. The proposed restrictions concern the terms on which specified foreign activities may be authorized in Greenland, not a transfer of Greenland’s sovereignty to Washington.
5. Denmark, Greenland, and the Legal Authority to Conclude the Deal
The September agreement involves the United States, the Kingdom of Denmark, and Greenland’s self-government. These participants do not possess identical constitutional or international legal powers. Greenland remains part of the Kingdom of Denmark and exercises extensive authority over transferred domestic responsibilities. The Danish government retains the Kingdom’s constitutional responsibility for foreign affairs and security policy, subject to the arrangements governing Greenlandic participation (Denmark, 2009, s. 11).
Section 19 of the Danish Constitution governs the Kingdom’s conduct of international affairs. It requires Folketing consent for commitments of major importance, obligations whose fulfillment requires parliamentary participation, and changes to the Kingdom’s territory. It also regulates the termination of treaties concluded with parliamentary consent. The constitutional requirements applicable to the new agreement depend on its terms and the procedures necessary to implement them (Denmark, 1953, s. 19).
Greenland’s involvement has a separate legal foundation. The Act on Greenland Self-Government establishes procedures for informing and consulting Naalakkersuisut, Greenland’s government, about international agreements of particular importance to Greenland. Where Denmark and Greenland have participated jointly in negotiations, the Act provides for joint signature to the widest extent possible. These arrangements recognize Greenland’s direct interest in decisions affecting its territory without making it an independent state for the purposes of the proposed defense agreement (Denmark, 2009, s. 13).
The September 18 announcement reflects that institutional relationship. Denmark’s Prime Minister’s Office identified all three governments as expected signatories. Danish Prime Minister Mette Frederiksen emphasized the Kingdom’s sovereignty, territorial integrity, and the Greenlandic people’s right to self-determination. Greenlandic Prime Minister Jens-Frederik Nielsen separately stressed that the agreement recognizes Greenland’s interests and its place in international cooperation (Prime Minister’s Office of Denmark, 2026).
Joint participation is significant for the agreement’s negotiation and implementation, but it does not establish that every required approval has already been obtained. The governments have announced an expected agreement and an anticipated signature. Its binding effect remains subject to the legal procedures identified in the official announcement.
5.1 Greenlandic Self-Government and Defense Policy
The Act on Greenland Self-Government entered into force on June 21, 2009, replacing the Home Rule arrangement established in 1979. It assigns legislative authority within transferred fields to Inatsisartut, Greenland’s parliament, and executive authority to Naalakkersuisut. The Act’s preamble recognizes the Greenlandic people’s right to self-determination under international law (Denmark, 2009, preamble and s. 1).
Greenland’s authority in international affairs is defined by Chapter 4 of the Act. Section 12 permits Naalakkersuisut to negotiate and conclude certain agreements on behalf of the Kingdom when they concern Greenland exclusively and relate entirely to fields of responsibility it has assumed. Agreements affecting defense and security policy are expressly excluded from that independent procedure and are instead governed by Section 13 (Denmark, 2009, ss. 11–13).
Section 13 requires the Danish government to inform Naalakkersuisut before negotiations begin on agreements of particular importance to Greenland. Such agreements must also be submitted to Naalakkersuisut for comments before their conclusion or termination. When Denmark and Greenland have been jointly involved in negotiations, the agreement is to be signed by the Danish government together with Naalakkersuisut to the widest extent possible. These requirements provide for Greenlandic participation while preserving the Danish authorities’ constitutional responsibilities.
The Act also addresses disagreement. Under Section 13(4), if the Danish government considers it necessary to conclude an agreement without Naalakkersuisut’s consent, the agreement is to have no effect for Greenland to the widest extent possible. This is not an absolute Greenlandic veto over every international agreement. Nor does the provision establish how a disagreement concerning the September security arrangement would be resolved. Its application depends on the agreement’s content and the relevant constitutional procedures (Denmark, 2009, s. 13(4)).
Greenlandic involvement in defense arrangements has an established precedent. The 2004 Igaliku amendment incorporated Greenland’s then Home Rule Government into the defense framework and provided for consultation concerning significant changes to American military operations or facilities. The 2009 Act subsequently expanded the constitutional framework for Greenlandic participation in international affairs. Neither instrument independently transfers the Kingdom’s defense and security responsibilities to Greenland (United States and Denmark, 2004, art. 3; Denmark, 2009).
The right to self-determination remains relevant to the September agreement’s territorial implications. Its recognition in the Self-Government Act and Frederiksen’s official statement is consistent with Greenland’s continuing constitutional position. It does not require treating the proposed expansion of American military authority as a transfer of sovereignty or extending the legal analysis into hypothetical changes to Greenland’s status.
5.2 Signature, Parliamentary Approval, and Entry Into Force
The September 18 announcement did not complete the legal process for bringing the new security agreement into force. Denmark’s Prime Minister’s Office stated that Greenland, Denmark, and the United States expected to sign the instrument during the following week’s United Nations General Assembly. The agreement would then be subject to the necessary national parliamentary procedures before entering into force (Prime Minister’s Office of Denmark, 2026).
Agreement on a text, signature, completion of domestic procedures, and entry into force are legally distinct events. Signature may establish a state’s consent to be bound where the parties have so agreed, but an instrument may instead require ratification, approval, or another specified procedure. The Danish announcement expressly identifies further parliamentary steps. It does not establish that signature alone will bring the new substantive obligations into operation.
Denmark’s constitutional process is governed in part by Section 19 of the Constitution. Folketing consent is required for obligations of major importance or commitments whose fulfillment requires parliamentary participation. The government has confirmed that parliamentary procedures are necessary for the proposed arrangement, although its announcement does not identify every approval measure or the instrument through which Denmark will ultimately express consent to be bound (Denmark, 1953, s. 19; Prime Minister’s Office of Denmark, 2026).
Greenlandic parliamentary involvement must be distinguished from Denmark’s constitutional requirements. The Danish Prime Minister’s Office’s 2023 guidance on matters concerning Greenland states that Naalakkersuisut must obtain Inatsisartut’s opinion on the ratification of international agreements that have effect for Greenland. An opinion from Inatsisartut, consent from Naalakkersuisut, and approval by the Folketing perform different functions. Their precise operation in relation to the proposed agreement depends on its final form and the procedures applicable to its conclusion (Prime Minister’s Office of Denmark, 2023, s. 5.9).
The pending agreement also does not suspend the existing legal basis for American military activities. The 1951 Defense Agreement and its 2004 amendment already regulate military facilities, access, and consultation. Any changes introduced by the September arrangement will need to be determined from its operative provisions and the rules governing its entry into force.
6. The Greenland Deal and Arctic Geopolitics
Greenland’s location connects the northern approaches to North America with the Arctic and North Atlantic. Its military infrastructure serves functions relevant to missile warning, space operations, and the defense of the United States and Canada. The island is also part of the Kingdom of Denmark, a NATO member whose responsibilities in the region extend beyond the American military presence (NATO, 2026; US Space Force, 2026).
The September agreement concerns an established security relationship. American forces have operated in Greenland under bilateral defense arrangements since 1951, while Denmark and its allies have undertaken additional investments and military activities in the Arctic. The proposed deal would develop that framework by addressing Washington’s demands for long-term access and restrictions on specified foreign activities.
The participating governments have emphasized different aspects of the arrangement. Trump presented it as securing enduring American authority to meet national security requirements. Frederiksen described it as strengthening security in the Arctic and North Atlantic while preserving the Kingdom’s sovereignty. Nielsen emphasized Greenland’s interests within international cooperation (Slattery et al., 2026; Prime Minister’s Office of Denmark, 2026).
These statements place the agreement within a wider relationship involving national defense, alliance commitments, and Greenlandic self-government. Its strategic importance rests on the existing military functions of the territory and the additional authority contemplated by the participating governments, rather than on any announced change in Greenland’s territorial status.
6.1 Greenland’s Role in North American Defense
Pituffik Space Base, formerly Thule Air Base, is a central element of the American military presence in Greenland. Its northern location supports operations connected with North American missile warning and military space systems. The installation’s established functions explain why access to Greenland has remained important to Washington independently of the September 2026 negotiations (US Space Force, n.d.).
The 12th Space Warning Squadron operates the Upgraded Early Warning Radar at Pituffik. Its missions include detecting and assessing intercontinental and sea-launched ballistic missile threats, providing information relevant to missile defense, and contributing to space surveillance. The radar supports warning arrangements serving the United States and Canada. These capabilities existed before the newly announced agreement (US Space Force, n.d.).
Pituffik also supports the Satellite Control Network. The 22nd Space Operations Squadron’s Detachment 7 operates a tracking station that provides telemetry, tracking, and commanding services for American and allied government satellites. Its high northern latitude permits frequent contact with satellites in polar orbits, connecting the installation’s geographical position with its operational functions (US Space Force, 2026).
An expanded American presence could involve additional facilities or greater operational activity, but the announcement does not establish which new capabilities will be deployed. Trump stated that the United States would develop a larger military presence. Reuters reported on September 18 that it remained unclear whether the agreement would lead to the construction of additional bases (Slattery et al., 2026). Existing radar and satellite-tracking functions must not be presented as accomplishments of the proposed arrangement.
6.2 Russia, China, and Strategic Competition in the Arctic
The reported restrictions on foreign bases and sensitive investments form part of Washington’s approach to strategic competition in the Arctic. NATO’s 2022 Strategic Concept identifies Russia as the most significant and direct threat to allied security. It separately characterizes China’s stated ambitions and coercive policies as challenges to allied interests, security, and values. Those are the alliance’s assessments; the document does not classify the two states in identical terms (NATO, 2022).
NATO’s July 2026 account of Arctic security identifies increased Russian military activity in the region, including the development and reopening of military facilities. It also points to the High North’s importance for reinforcement routes and communications across the North Atlantic. These regional developments help explain why Greenland’s position matters to allied defense planning without establishing a Russian military presence in Greenland itself (NATO, 2026).
China’s documented interests include Arctic energy resources, critical minerals, and maritime routes, according to NATO. Commercial investment has also attracted American attention in Greenland. In January 2025, Tanbreez Mining’s chief executive told Reuters that American and Danish officials had urged the company not to sell its rare-earth project to Chinese-linked buyers. That reported episode concerns a commercial transaction and does not demonstrate that China maintains a military base in Greenland or has sought one under the September arrangement (Burton and Scheyder, 2025; NATO, 2026).
The proposed agreement addresses military access and investment through different reported restrictions. Trump referred to American adversaries, while an anonymous State Department official described a prohibition on non-NATO military bases and limitations on unspecified sensitive investments. The difference matters because the categories of states and activities covered by those formulations are not necessarily the same (Slattery et al., 2026).
Restrictions governing Greenland could affect access to strategically significant facilities and projects within the territory. They would not give the United States authority over other Arctic states or the region as a whole. Their practical effect also depends on the scope of the final agreement and the arrangements through which the participating governments implement it.
6.3 The Agreement and Transatlantic Security Relations
The September negotiations followed a period of tension over Trump’s proposals to acquire Greenland. Denmark and Greenland opposed a transfer of the territory, while the United States continued to seek broader security arrangements. The announced agreement addresses American defense demands through negotiations that expressly preserve the Kingdom’s sovereignty. That distinction is central to understanding the diplomatic outcome described by the participating governments (Slattery et al., 2026; Prime Minister’s Office of Denmark, 2026).
Greenland was already connected to NATO’s collective-defense framework before the announcement. Article 6 of the North Atlantic Treaty includes islands under the jurisdiction of member states in the North Atlantic area north of the Tropic of Cancer within the geographical scope relevant to Article 5. Greenland falls within that description. Article 5 requires each ally to assist a member subjected to an armed attack, but leaves the choice of action, including any use of armed force, to what that ally considers necessary (NATO, 1949, arts 5–6).
Collective-defense obligations do not themselves determine where an ally may establish military installations or the operational powers it may exercise within another member’s territory. Those matters require separate arrangements. The 1951 Defense Agreement and its 2004 amendment provide the established bilateral framework for American activities in Greenland, while the proposed September agreement concerns its further development (United States and Denmark, 1951, 2004).
Denmark has also undertaken substantial Arctic defense commitments. On October 10, 2025, its Ministry of Defence announced a second Arctic and North Atlantic defense agreement involving planned acquisitions totaling DKK 27.4 billion. The measures include additional Arctic vessels, maritime patrol capability, drones, air-surveillance infrastructure, and a new headquarters for Joint Arctic Command. These are Danish defense initiatives developed in cooperation with Greenland and the Faroe Islands, not capabilities created by the September 2026 American announcement (Danish Ministry of Defence, 2025).
During 2026, the Danish Armed Forces also increased their presence and training activities in and around Greenland in cooperation with NATO allies. The announced activities included exercises involving aircraft, vessels, and military personnel, as well as training relevant to Arctic operations and the protection of critical infrastructure. This cooperation demonstrates that Greenland’s security arrangements involve multiple allied forces and continuing Danish responsibilities (Danish Defence Command, 2026).
The proposed US Greenland deal must be understood within those existing relationships. It concerns the extent of American military access and the reported restrictions on certain third-country activities, while Denmark retains responsibility for the Kingdom’s defense and Greenland participates through its constitutional institutions. The governments have announced a common security arrangement, but the final allocation of particular powers remains dependent on the agreement’s legal terms.
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Conclusion
The US Greenland deal announced on September 18, 2026, does not transfer sovereignty over Greenland to the United States. Greenland remains a self-governing part of the Kingdom of Denmark. Danish Prime Minister Mette Frederiksen expressly affirmed that the proposed agreement recognizes the Kingdom’s sovereignty and territorial integrity and the Greenlandic people’s right to self-determination. Greenlandic Prime Minister Jens-Frederik Nielsen separately emphasized the recognition of Greenland’s interests and its place in international cooperation (Prime Minister’s Office of Denmark, 2026).
The agreement’s legal significance rests on the additional security powers it may establish. The United States already possesses extensive military access, basing, and overflight rights under the 1951 Defense Agreement and its 2004 amendment. The newly reported restrictions on foreign military installations and sensitive investments could extend Washington’s role in specified decisions, but the precise scope of those powers cannot be determined from the public announcements alone.
Greenland’s geographical position gives the arrangement wider significance for North American defense, NATO cooperation, and Arctic security. Expanded American military authority within Greenland would not, by itself, change the territory’s sovereignty. The final agreement and completion of the required parliamentary procedures will determine which additional rights become legally operative and how they interact with the continuing responsibilities of Denmark and Greenland.
References
Act on Greenland Self-Government (2009) Act No. 473 of 12 June 2009, entered into force 21 June 2009, Lovtidende A.
Agreement between the Government of the United States of America and the Government of the Kingdom of Denmark pursuant to the North Atlantic Treaty, concerning the defense of Greenland (1951) signed at Copenhagen, 27 April 1951, entered into force 8 June 1951, 94 UNTS 35.
Agreement between the Government of the United States of America and the Government of the Kingdom of Denmark, including the Home Rule Government of Greenland, to amend and supplement the Agreement of 27 April 1951 pursuant to the North Atlantic Treaty between the Government of the United States of America and the Government of the Kingdom of Denmark concerning the defense of Greenland (Defense Agreement), including relevant subsequent agreements related thereto (2004) signed at Igaliku, 6 August 2004, entered into force 6 August 2004, 2335 UNTS 32.
Agreement between the Parties to the North Atlantic Treaty regarding the Status of Their Forces (1951) signed at London, 19 June 1951, entered into force 23 August 1953, 199 UNTS 67.
Burton, M. and Scheyder, E. (2025) ‘US lobbied Greenland rare earths developer Tanbreez not to sell to China’, Reuters, 9 January [online]. Available at: https://www.reuters.com/markets/commodities/us-lobbied-greenland-rare-earths-developer-tanbreez-not-sell-china-2025-01-09/ (Accessed: 19 September 2026).
Constitutional Act of Denmark (1953) 5 June 1953. English translation published by the Folketing, Copenhagen, 2013.
Danish Defence Command (2026) ‘The Danish Armed Forces increases presence and training activity in and around Greenland’, 15 January [online]. Available at: https://www.forsvaret.dk/en/news/2026/forsvarets-ogede-tilstedevarelse-og-ovelsesaktivitet-i-gronland-2026/ (Accessed: 19 September 2026).
Danish Ministry of Defence (2025) ‘The Second Agreement on the Arctic and North Atlantic strengthens the operational effectiveness of the Danish Armed Forces with new acquisitions totalling DKK 27.4 billion’, 10 October [online]. Available at: https://www.fmn.dk/en/news/2025/the-second-agreement-on-the-arctic-and-north-atlantic-strengthens-the-operational-effectiveness-of-the-danish-armed-forces-with-new-acquisitions-totalling-dkk-27.4-billion (Accessed: 19 September 2026).
European Commission (2026) ‘EU and Greenland strengthen partnership and engagement, backed by €200 million in EU investment’, 7 September [online]. Available at: https://digital-strategy.ec.europa.eu/en/news/eu-and-greenland-strengthen-partnership-and-engagement-backed-eu200-million-eu-investment (Accessed: 19 September 2026).
NATO (2022) NATO 2022 Strategic Concept. Adopted by the Heads of State and Government at the NATO Summit in Madrid, 29 June [online]. Available at: https://www.nato.int/en/about-us/official-texts-and-resources/strategic-concepts/nato-2022-strategic-concept (Accessed: 19 September 2026).
NATO (2026) ‘Arctic security’, updated 24 July [online]. Available at: https://www.nato.int/en/what-we-do/deterrence-and-defence/arctic-security (Accessed: 19 September 2026).
North Atlantic Treaty (1949) signed at Washington, 4 April 1949, entered into force 24 August 1949, 34 UNTS 243.
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Prime Minister’s Office of Denmark (2023) Vejledning om ministeriers behandling af sager vedrørende Grønland [Guidelines on ministries’ handling of matters concerning Greenland], Guidance No. 9001 of 2 January [online]. Available at: https://www.retsinformation.dk/eli/retsinfo/2023/9001 (Accessed: 19 September 2026).
Prime Minister’s Office of Denmark (2026) ‘Expected agreement on strengthened security in the Arctic and the North Atlantic Area’, 18 September [online]. Available at: https://stm.dk/en/press/press-releases/expected-agreement-on-strengthened-security-in-the-arctic-and-the-north-atlantic-area/ (Accessed: 19 September 2026).
Slattery, G., Banco, E., Gronholt-Pedersen, J. and Jacobsen, S. (2026) ‘US and Denmark reach deal on Greenland, Trump says’, Reuters, 18 September [online]. Available at: https://www.reuters.com/world/china/us-denmark-close-greenland-deal-sources-say-2026-09-18/ (Accessed: 19 September 2026).
United States Department of State (n.d.) ‘Vienna Convention on the Law of Treaties’ [online]. Available at: https://2009-2017.state.gov/s/l/treaty/authorities/international/62785.htm (Accessed: 19 September 2026).
United States Space Force (n.d.) ‘Pituffik SB, Greenland’ [online]. Available at: https://www.petersonschriever.spaceforce.mil/Pituffik-SB-Greenland/?dvpTag=Army&dvpmoduleid=54284 (Accessed: 19 September 2026).
United States Space Force (2026) ‘Translating Orbital Capabilities into Multi-Domain Lethality: The SCN at Pituffik’, 26 May [online]. Available at: https://www.ussf-cfc.spaceforce.mil/News/Article-Display/Article/4500821/translating-orbital-capabilities-into-multi-domain-lethality-the-scn-at-pituffik (Accessed: 19 September 2026).
Vienna Convention on the Law of Treaties (1969) adopted 22 May 1969, opened for signature at Vienna 23 May 1969, entered into force 27 January 1980, 1155 UNTS 331.
