INTRODUCTION
In January 2026, President Donald Trump revived his administration’s interest in acquiring Greenland, announcing what he described as a “framework of a future deal” with Denmark regarding the autonomous Arctic territory.1 This proposal, which follows similar unsuccessful attempts in 2019, has reignited fundamental debates about the legality of territorial acquisition in the contemporary international legal order.2 While historical precedents such as the 1867 Alaska Purchase demonstrate that territorial transfers through purchase were once permissible, the question remains whether such transactions comport with the profound transformation of international law following the establishment of the United Nations in 1945.
The research question this paper addresses is whether the proposed acquisition of Greenland by the United States, whether through outright purchase, partial sovereignty transfer, or any arrangement not originating from the free consent of Greenland’s people, complies with contemporary international law principles governing territorial sovereignty, self-determination, and the prohibition on non-consensual territorial acquisition. This inquiry is particularly salient given President Trump’s refusal to initially rule out military force and subsequent threats of economic repercussions against Denmark and its European allies if his demands were not accommodated.3
This paper argues that any non-consensual acquisition of Greenland violates fundamental norms of modern international law. Specifically, such acquisition contravenes the right to self-determination enshrined in the UN Charter and the International Covenants,4 the absolute prohibition on territorial acquisition through threat or use of force articulated in Article 2(4) of the UN Charter,5 and the post-1945 legal framework that categorically rejects colonial-era models permitting territorial transfers without the consent of affected populations.6 Greenland’s legally recognized status as a self-determination unit under Denmark’s 2009 Self-Government Act further reinforces these protections.7
Methodologically, this paper employs doctrinal legal analysis, examining primary sources including treaty provisions, customary international law principles, and jurisprudence from the International Court of Justice alongside authoritative secondary scholarship. The analysis proceeds in four parts: Part II examines self-determination as a peremptory norm of international law; Part III analyzes the prohibition on non-consensual territorial acquisition and its scope; Part IV contrasts colonial-era land transfer doctrines with the post-1945 legal paradigm; and Part V applies these principles to evaluate the legal permissibility of the Greenland proposal under contemporary international law.
SELF-DETERMINATION AS A FUNDAMENTAL PRINCIPLE OF INTERNATIONAL LAW
A. Legal Foundations of Self-Determination
The principle of self-determination has evolved from a political aspiration into a fundamental legal right that constitutes a cornerstone of the contemporary international legal order. Article 1(2) of the United Nations Charter establishes as one of the UN’s principal purposes the development of “friendly relations among nations based on respect for the principle of equal rights and self-determination of peoples.”8 This foundational provision, read in conjunction with Article 55, which reaffirms the principle of self-determination, embeds the concept within the normative framework governing state behavior.9
The principle gained binding legal force through the 1960 Declaration on the Granting of Independence to Colonial Countries and Peoples, which proclaimed that “all peoples have the right to self-determination” and that “by virtue of that right they freely determine their political status and freely pursue their economic, social and cultural development.”10 The Declaration categorically stated that subjection of peoples to alien subjugation and exploitation constitutes a denial of fundamental human rights contrary to the UN Charter.11
Treaty codification of self-determination as an enforceable legal right occurred through the 1966 International Covenants on Human Rights. Common Article 1 of both the International Covenant on Economic, Social and Cultural Rights and the International Covenant on Civil and Political Rights provides that “all peoples have the right of self-determination” and “by virtue of that right they freely determine their political status and freely pursue their economic, social and cultural development.”12 Importantly, Article 1(2) of both Covenants establishes that “in no case may a people be deprived of its own means of subsistence,” linking self-determination to permanent sovereignty over natural resources.13
The International Court of Justice has recognized self-determination as possessing erga omnes character, meaning it creates obligations owed to the international community as a whole.14 In the East Timor case, the Court described self-determination as “one of the essential principles of contemporary international law,” binding all states.15 The 1970 Declaration on Friendly Relations reinforced this principle as customary international law, providing that states have a duty to promote self-determination and to refrain from any forcible action that deprives peoples of their right to self-determination.16 Scholars widely recognize that self-determination has attained the status of jus cogens, a peremptory norm from which no derogation is permitted.17
B. Greenland’s Self-Determination Status
Denmark’s constitutional relationship with Greenland has evolved substantially from colonial administration to recognition of Greenlandic self-determination rights. The critical legal instrument governing this relationship is the 2009 Act on Greenland Self-Government, which explicitly acknowledges “that the people of Greenland is a people pursuant to international law with the right of self-determination.”18 This recognition carries significant legal consequences under international law, transforming Greenland from a constituent part of the Danish realm into a distinct self-determination unit whose political future must be determined by its own population.
The Self-Government Act transferred substantial competencies to Greenlandic authorities, including control over natural resources, judicial administration, policing, and most aspects of domestic governance.19 Critically, Section 21 of the Act establishes that independence for Greenland may be decided through a referendum among Greenland’s approximately 57,000 inhabitants, followed by negotiations with the Danish government and approval by both the Greenlandic Parliament and the Danish Folketing.20 This framework demonstrates that sovereignty over Greenland’s political status resides with the Greenlandic people themselves, not exclusively with Denmark.
Denmark’s recognition of Greenlandic self-determination is further reinforced by international practice. The United States itself has repeatedly recognized Danish sovereignty over Greenland through bilateral agreements, including the 1951 Defense Agreement and the 2004 Agreement to Amend and Supplement the Agreement.21 These agreements, negotiated during periods when Greenland possessed less autonomy than today, establish US recognition of the existing constitutional arrangement and preclude subsequent challenges to Greenland’s legal status under Denmark’s jurisdiction.
The international legal significance of Greenland’s status is clear: any alteration to Greenland’s political status, territorial integrity, or sovereign rights requires the free and genuine consent of the Greenlandic people expressed through democratic processes. Self-determination operates as a shield protecting Greenland from external imposition of sovereignty transfers, regardless of agreement between the United States and Denmark. As the holders of self-determination rights, Greenlanders cannot have their political future determined by external powers, even if one of those powers currently exercises formal sovereignty over their territory.
PROHIBITION ON NON-CONSENSUAL ACQUISITION OF TERRITORY
A. The Absolute Prohibition Under Contemporary International Law
Modern international law establishes an absolute prohibition on the acquisition of territory through non-consensual means, representing one of the most fundamental transformations in the post-1945 legal order. Article 2(4) of the UN Charter provides that “all Members shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state.”22 This provision fundamentally altered the historical doctrine that permitted conquest and forcible territorial acquisition, establishing territorial integrity as a foundational principle of the international system.
The prohibition on territorial acquisition through force operates as a corollary to Article 2(4)’s prohibition on the use of force itself. The International Court of Justice affirmed this connection in multiple decisions, recognizing that “the prohibition of territorial acquisition resulting from the threat or use of force” constitutes a principle of customary international law binding on all states regardless of treaty ratification.23 This customary status ensures the prohibition applies universally, not merely among UN member states.
The UN Security Council has consistently reaffirmed the inadmissibility of territorial acquisition by force. Beginning with Resolution 242 following the 1967 Arab-Israeli War, the Council emphasized “the inadmissibility of the acquisition of territory by war” as a foundational principle.24 Subsequent resolutions addressing conflicts in Cyprus, the Falkland Islands, Kuwait, Georgia, Crimea, and other contexts have reiterated this principle on at least eight occasions, establishing consistent state practice supporting the prohibition.25
The absolute character of this prohibition means it applies regardless of the circumstances under which territory is acquired. As the UN Special Rapporteur on the situation of human rights in the Palestinian territories explained, the prohibition operates “whether the occupied territory was acquired through a war of aggression or a defensive war.”26 No exception exists for territories acquired while repelling aggression or through supposedly defensive military operations. The prohibition’s peremptory nature reflects the international community’s judgment that territorial stability and sovereign equality outweigh any justifications for forcible territorial change.
B. Scope Beyond Military Force
While the prohibition on territorial acquisition clearly encompasses military conquest and occupation, its scope extends significantly beyond conventional armed force. The 1970 Declaration on Friendly Relations provides that “the territory of a State shall not be the object of acquisition by another State resulting from the threat or use of force. No territorial acquisition resulting from the threat or use of force shall be recognized as legal.”27 The Declaration’s reference to both “threat” and “use” of force indicates that actual military action is unnecessary; the threat alone suffices to vitiate any purported territorial transfer.
The concept of “force” in Article 2(4) has been subject to interpretive debate regarding whether it encompasses economic and political coercion. While the travaux préparatoires of the UN Charter suggest the drafters primarily contemplated armed force, subsequent state practice and authoritative interpretations support a broader reading.28 The 1970 Declaration on Friendly Relations provides that “no State may use or encourage the use of economic, political or any other type of measures to coerce another State in order to obtain from it the subordination of the exercise of its sovereign rights.”29 Although this provision does not explicitly reference territorial acquisition, it establishes that severe economic coercion intended to subordinate sovereign rights violates international law.
Modern international law also incorporates the non-recognition doctrine, which obligates states to withhold recognition from territorial changes achieved through prohibited means. When Russia annexed Crimea in 2014, the UN General Assembly adopted Resolution 68/262 declaring the referendum invalid and calling on states not to recognize any alteration of Crimea’s status.30 Similarly, the international community has refused to recognize annexations in other contexts, creating what one UN expert described as a “dampening effect” on territorial conquest.31 This non-recognition practice reinforces the prohibition by denying legal effect to purported territorial transfers accomplished through impermissible means.
The principle of ex injuria jus non oritur provides theoretical foundation for the non-recognition doctrine: unlawful acts cannot create legal rights. A state cannot acquire valid territorial title through means prohibited by international law, regardless of subsequent effective control or the passage of time. This principle ensures that the prohibition on non-consensual territorial acquisition retains practical force rather than becoming merely aspirational.
C. Application to Economic Transactions Under Duress
The critical question for evaluating territorial purchases is whether transactions nominally characterized as voluntary sales fall within the prohibition when negotiated under economic or military pressure. International law recognizes that consent obtained through coercion is invalid. The Vienna Convention on the Law of Treaties provides that a treaty is void if its conclusion was procured through the threat or use of force in violation of international law.32 While this provision specifically addresses armed force, the principle that coerced consent is no consent applies broadly across international law.
President Trump’s January 2026 statements regarding Greenland raise substantial questions about the voluntariness of any resulting agreement. Initially refusing to rule out military force to acquire Greenland, Trump subsequently threatened “economic repercussions” for Denmark and suggested potential tariffs on European allies if his demands were not accommodated.33 These statements occurred in the context of Trump’s broader threats to withdraw from NATO or reduce US security commitments to Europe unless allies increased defense spending and acceded to US preferences.34
Any purchase agreement or sovereignty transfer negotiated following such threats would constitute acquisition through “threat of force” within the meaning of Article 2(4), even if the final transaction appears consensual on its face. The relevant inquiry is not whether force was ultimately used, but whether the threat of force or severe economic coercion influenced the decision to transfer territory. A state facing credible threats of economic sanctions, trade wars, or withdrawal of security guarantees cannot be said to consent freely to territorial transfers demanded under such pressure.
Furthermore, the Greenland proposal involves not merely Denmark but the Greenlandic people themselves, whose opposition to US sovereignty has been clearly expressed. Greenland’s Prime Minister stated that “sovereignty is a red line” and rejected US sovereignty over military installations, emphasizing that Greenland is “not for sale.”35 When the population holding self-determination rights opposes territorial transfer, any agreement between external powers regardless of its nominally voluntary character violates the prohibition on non-consensual acquisition.
The combination of threatened economic coercion against Denmark, the absence of Greenlandic consent, and the broader context of pressure tactics transforms what might superficially appear as a commercial transaction into prohibited non-consensual territorial acquisition. Modern international law does not permit powerful states to circumvent fundamental prohibitions by characterizing coerced transfers as purchases.
COLONIAL-ERA TRANSFERS VS. POST-1945 LEGAL FRAMEWORK
A. Colonial-Era Territorial Acquisition Doctrines
The legal framework governing territorial acquisition prior to 1945 operated under fundamentally different premises than contemporary international law, permitting methods of territorial transfer that would be categorically unlawful today. Colonial powers relied extensively on the doctrine of terra nullius, treating inhabited territories as legally empty if deemed insufficiently developed according to European standards of “civilization.”36 This doctrine enabled European states to claim original title over vast territories through symbolic acts of discovery and occupation, regardless of indigenous populations’ presence or established governance structures.
The discovery doctrine, closely related to terra nullius, permitted European powers to acquire territorial sovereignty through first discovery followed by effective occupation.37 International law during this period prioritized relationships among European states rather than rights of non-European peoples. The Berlin Conference of 1884-1885 exemplified this approach, with European powers dividing Africa among themselves through mutual recognition without regard for African political structures or territorial claims.
Colonial-era law also recognized territorial cession through treaties with local rulers, even when negotiated under fundamentally unequal power dynamics and dubious consent.38 Metropolitan powers frequently obtained territorial rights through agreements signed under threat of military force or following demonstrations of superior weaponry. The doctrine of effectiveness, which granted territorial title based on actual control rather than legitimacy of acquisition, further reinforced this system by validating territorial claims of states exercising administrative authority regardless of how that authority was initially obtained.39
The 1867 Alaska Purchase illustrates the colonial-era approach to territorial transfers. Russia and the United States negotiated the sale of Alaska for $7.2 million without any consultation with or consent from Alaska’s indigenous populations.40 International law at that time imposed no requirement for local consent; territory could be transferred between sovereign states through bilateral agreement, with affected populations treated as objects rather than subjects of the transaction. This transaction, though involving the same parties and Arctic territories as the current Greenland proposal, occurred within a legal framework that modern international law has comprehensively rejected.
B. Post-1945 Paradigm Shift
The establishment of the United Nations in 1945 marked a fundamental transformation in the international legal framework governing territorial sovereignty. The UN Charter’s prohibition on the threat or use of force against territorial integrity represented a decisive break from the prior regime that had permitted territorial acquisition through conquest.41 While the 1928 Kellogg-Briand Pact initiated movement toward prohibiting aggressive war, the Charter institutionalized comprehensive prohibitions and established enforcement mechanisms through the Security Council.42
The decolonization movement fundamentally challenged colonial-era assumptions about territorial sovereignty. The 1960 Declaration on the Granting of Independence to Colonial Countries and Peoples proclaimed that “the subjection of peoples to alien subjugation, domination and exploitation constitutes a denial of fundamental human rights” and is “contrary to the Charter of the United Nations.”43 This Declaration reversed the colonial presumption that powerful states could legitimately exercise sovereignty over distant territories and transfer such sovereignty without consulting affected populations.
The 1970 Declaration on Friendly Relations reinforced this transformation, establishing that “every State has the duty to promote, through joint and separate action, realization of the principle of equal rights and self-determination of peoples.”44 Importantly, the Declaration provided that territory of a state shall not be the object of military occupation or acquisition resulting from threat or use of force, and that “no territorial acquisition resulting from the threat or use of force shall be recognized as legal.”45
Post-colonial international law adopted the principle of uti possidetis juris to manage the transition from colonial to independent status. This principle freezes colonial boundaries at independence, transforming former administrative divisions into international boundaries to prevent territorial disputes and protect newly independent states’ territorial integrity.46 While originally developed in Latin American independence movements, the International Court of Justice applied uti possidetis in African boundary disputes, recognizing it as a general principle preventing forcible boundary alteration.47
The paradigm shift extends beyond formal decolonization to fundamentally reconceptualize the relationship between states and peoples. Modern international law treats peoples as rights-bearing subjects rather than objects of state power. This transformation means that territorial sovereignty cannot be transferred as though peoples and territories were commodities subject to sale or exchange between states.
C. Incompatibility of Historical Precedents with Modern Law
The Alaska Purchase, though superficially analogous to the Greenland proposal, occurred under a legal regime so fundamentally different that it provides no support for the legality of contemporary territorial purchases. In 1867, international law imposed no requirement for indigenous consent to territorial transfers; by contrast, modern international law makes self-determination a fundamental right and prohibits territorial transfers without the consent of affected peoples.48 The temporal difference is not merely chronological but represents a categorical transformation in legal norms.
The International Court of Justice’s 1975 Advisory Opinion on Western Sahara confirmed that historical treaties purporting to establish territorial sovereignty cannot validate territorial claims when those treaties lacked genuine consent from affected populations.49 The Court examined whether Western Sahara was terra nullius at the time of Spanish colonization and whether historical agreements with local leaders established valid sovereignty.50 The Court concluded that such agreements, even if they existed, could not override the self-determination rights of the Saharan people under contemporary international law.
Greenland’s constitutional evolution reflects this paradigm shift. Prior to 1953, Greenland was administered as a Danish colony under policies that restricted Greenlandic autonomy and economic development.51 Denmark’s 1953 constitutional revision integrated Greenland as a county with representation in the Folketing, and the 2009 Self-Government Act recognized Greenlanders as a people under international law with self-determination rights.52 This transformation from colonial possession to self-determination unit means that Greenland’s legal status today differs categorically from Alaska’s status in 1867.
The fundamental principle underlying this paradigm shift is that peoples possess inherent rights that states must respect. Territorial sovereignty derives from and must serve the interests of peoples themselves, not the strategic or economic interests of external powers. Historical precedents permitting territorial purchases without local consent reflect a discredited legal order incompatible with contemporary international law’s foundational principles.
DOCTRINAL APPLICATION: THE GREENLAND PROPOSAL UNDER INTERNATIONAL LAW
A. Violations of Self-Determination
Application of self-determination principles to the Greenland proposal reveals fundamental legal deficiencies. The proposal originates from external powers without demonstrated support from Greenland’s population, whose consent is legally required under both international law and Danish constitutional arrangements. Greenland’s Prime Minister has explicitly rejected US sovereignty claims, stating that “sovereignty is a red line” and emphasizing that Greenland is “not for sale.”53 This clear expression of opposition from Greenlandic leadership, representing the territory’s self-governing institutions, demonstrates the absence of consent from the self-determination unit itself.
The 2009 Self-Government Act’s recognition of Greenlanders as “a people pursuant to international law with the right of self-determination” means that sovereignty over Greenland’s political future resides with the Greenlandic people themselves, not exclusively with Denmark.54 Denmark cannot unilaterally alienate Greenlandic territory or sovereignty rights because these rights vest in Greenlanders under international law. Any agreement between the United States and Denmark that transfers Greenlandic territory or sovereignty without Greenlandic consent violates the fundamental principle that peoples, not merely states, hold self-determination rights.
The reported “framework” negotiations involving potential transfer of sovereignty over portions of Greenlandic territory for US military installations further illustrates this violation.55 Even partial sovereignty transfers affecting Greenlandic territorial integrity require Greenlandic consent through the democratic processes established in the Self-Government Act, including referendum procedures for status changes.56 External powers cannot negotiate away the territorial integrity of a self-determination unit without violating its fundamental rights.
B. Non-Consensual Acquisition Analysis
The Greenland proposal exhibits multiple elements of prohibited non-consensual acquisition. President Trump’s initial refusal to rule out military force, combined with subsequent threats of economic repercussions against Denmark and potential tariffs on European allies, constitutes “threat of force” within the meaning of Article 2(4) of the UN Charter.57 The economic coercion component is particularly significant given the broader context of threatened NATO withdrawal and reduction of US security commitments unless European allies accede to American preferences.
Any territorial agreement negotiated under such circumstances cannot be considered voluntary, even if the final transaction appears consensual in form. The Vienna Convention on the Law of Treaties establishes that treaties procured through threat or use of force are void.58 While that provision specifically addresses armed force, the principle that coerced consent is invalid applies broadly across international law. A purchase agreement or sovereignty transfer negotiated following credible threats of economic sanctions, trade wars, or security guarantee withdrawals fails the voluntariness requirement essential for valid consent.
The reported framework involving partial sovereignty transfers over “pockets of Greenlandic territory” raises additional concerns.59 Such arrangements, negotiated under pressure and without Greenlandic consent, would constitute prohibited territorial acquisition regardless of whether characterized as purchase, lease, or sovereignty sharing. The critical question is not the transaction’s formal structure but whether it results in non-consensual acquisition of territory through threat of force or severe coercion.
Furthermore, the absence of Greenlandic consent transforms any US-Denmark agreement into an impermissible arrangement between external powers regarding territory whose political future belongs to its inhabitants. Modern international law prohibits precisely such arrangements, which treat peoples and territories as objects of interstate bargaining rather than as rights-bearing subjects whose consent is legally required.
C. Rejection of Colonial Analogies
Proponents of the Greenland proposal frequently invoke the Alaska Purchase as precedent, arguing that if the United States could legally purchase Alaska from Russia in 1867, similar transactions remain permissible today.60 This analogy fails because it ignores the fundamental transformation of international law between 1867 and the present.
The Alaska Purchase occurred within a legal framework that treated territories and peoples as commodities subject to interstate sale without consultation of affected populations. International law in 1867 imposed no requirement for indigenous consent to territorial transfers; metropolitan powers could freely alienate colonial possessions through bilateral agreement.61 This legal regime has been comprehensively rejected by post-1945 international law, which establishes self-determination as a fundamental right and prohibits territorial transfers without consent of affected peoples.
Greenland’s contemporary legal status differs categorically from Alaska’s status in 1867. Greenland is recognized under Danish law and international practice as a self-determination unit whose people hold the right to determine their political future.62 This recognition, formalized in the 2009 Self-Government Act, means that Greenland cannot be transferred through agreement between Denmark and the United States any more than Scotland could be transferred through agreement between the United Kingdom and France without Scottish consent.
The Danish constitution itself imposes limitations on territorial transfers. While the Folketing possesses authority over matters of sovereignty, the Self-Government Act establishes that changes to Greenland’s status require referendum approval among Greenlanders followed by negotiations and parliamentary approval.63 Denmark cannot lawfully circumvent these requirements through executive agreement with the United States.
D. Limited Lawful Alternatives
While non-consensual acquisition violates international law, limited alternatives exist that could address legitimate US security interests while respecting Greenland’s rights. Arrangements freely negotiated by Greenland itself, such as expanded US military presence through lease agreements or enhanced security cooperation, would comply with international law provided they meet several conditions.64
First, such arrangements must originate from Greenlandic democratic processes rather than external pressure. Greenland’s government would need to initiate or genuinely consent to negotiations without coercion from either the United States or Denmark. Second, any agreements must preserve Greenlandic territorial integrity and self-determination, meaning they cannot involve sovereignty transfers or create permanent territorial changes without referendum approval. Third, negotiations must occur free from threats of economic sanctions, military force, or other forms of coercion that would vitiate consent.
Enhanced NATO security infrastructure on Greenlandic territory represents another potentially lawful avenue, as NATO presence already exists through Danish membership and the existing US-Denmark Defense Agreement.65 Expansion of such arrangements through genuinely voluntary negotiations with Greenland could address US strategic concerns regarding Arctic security, Chinese influence, and military installations without violating territorial sovereignty or self-determination principles.
The critical distinction between lawful and unlawful approaches centers on consent. Security arrangements negotiated with Greenland’s free and informed consent, preserving Greenlandic territorial integrity and self-determination, remain permissible. Conversely, any attempt to acquire Greenlandic territory or sovereignty through purchase, pressure, or partial transfer without Greenlandic consent constitutes a flagrant violation of fundamental principles of modern international law.
CONCLUSION
Modern international law has categorically rejected the colonial-era framework that permitted powerful states to purchase territories or transfer sovereignty without the consent of affected populations. The Greenland proposal confronts three insurmountable legal barriers that render any non-consensual acquisition fundamentally incompatible with contemporary international law.
First, Greenland’s internationally recognized status as a self-determination unit means that any alteration to its political status, territorial integrity, or sovereign rights requires the free and genuine consent of the Greenlandic people expressed through democratic processes.66 Denmark cannot lawfully alienate Greenlandic territory or sovereignty because these rights vest in Greenlanders themselves under both the 2009 Self-Government Act and general principles of international law.67 The clear opposition expressed by Greenlandic leadership demonstrates the absence of requisite consent.
Second, the prohibition on territorial acquisition through threat or use of force establishes that agreements negotiated under economic or military pressure lack the voluntariness essential for valid consent.68 President Trump’s threats of economic repercussions and initial refusal to rule out military force transform what might superficially appear as a commercial transaction into prohibited non-consensual territorial acquisition.69 The Vienna Convention’s principle that coerced treaties are void applies with particular force to territorial transfers, where the stakes for affected populations are most profound.70
Third, the fundamental incompatibility between colonial-era territorial transfers and post-1945 legal frameworks means that historical precedents like the Alaska Purchase provide no support for contemporary territorial acquisitions. The 1867 purchase occurred within a legal regime that treated peoples and territories as commodities subject to interstate sale, a regime comprehensively rejected by the UN Charter system and decolonization movement.71 Modern international law treats peoples as rights-bearing subjects whose consent cannot be bypassed through agreements between external powers.
The research question posed at the outset asks whether sovereignty can be bought under modern international law. The answer is unequivocal: sovereignty cannot be “bought” when the transaction occurs without the free and genuine consent of the people whose sovereignty is at stake. The element of threatened economic or military coercion further vitiates any purported transfer, rendering it void under international law regardless of its formal characterization as purchase, lease, or sovereignty sharing.
The international community’s response to the Greenland proposal demonstrates that contemporary international law, when supported by collective resolve, effectively constrains even the most powerful states. European leaders have unanimously rejected any non-consensual territorial changes, the UN Secretary-General has reaffirmed self-determination principles, and legal scholars have emphasized the proposal’s incompatibility with fundamental legal norms.72 This unified response reflects recognition that permitting territorial purchases through coercion would undermine the entire post-1945 legal order and revive discredited colonial-era practices.
While security cooperation and economic arrangements remain legally permissible through genuine negotiation, any attempt to acquire Greenlandic territory or sovereignty through purchase, pressure, or partial transfer without Greenlandic consent constitutes a flagrant violation of fundamental principles of modern international law. The legal answer is clear and admits of no exception: in the post-1945 international order, sovereignty cannot be bought. It can only be exercised by the peoples who possess it, and altered only through their free and informed consent.
*****
Footnotes
1. David E. Sanger & Steven Erlanger, After Trump’s Ultimatum, Greenland Talks Include Possible U.S. Military Expansion, N.Y. Times (Jan. 22, 2026), https://www.nytimes.com/2026/01/22/world/europe/trump-greenland-deal-framework.html.
2. Helena Humphrey, Why Does Trump Want Greenland, and What Could It Mean for Denmark and the U.S.?, BBC News (Jan. 8, 2025), https://www.bbc.com/news/articles/c74x4m71pmjo.
3. Trump’s Greenland ‘Framework’ Deal: What We Know About It, What We Don’t, Al Jazeera (Jan. 22, 2026), https://www.aljazeera.com/news/2026/1/22/trumps-greenland-framework-deal-what-we-know-about-it-what-we-dont.
4. U.N. Charter art. 1, ¶ 2; International Covenant on Economic, Social and Cultural Rights art. 1, Dec. 16, 1966, 993 U.N.T.S. 3; International Covenant on Civil and Political Rights art. 1, Dec. 16, 1966, 999 U.N.T.S. 171.
5. U.N. Charter art. 2, ¶ 4.
6. Declaration on Principles of International Law Concerning Friendly Relations and Co-operation Among States in Accordance with the Charter of the United Nations, G.A. Res. 2625 (XXV), U.N. Doc. A/RES/2625(XXV) (Oct. 24, 1970).
7. Act on Greenland Self-Government, Act No. 473 (June 12, 2009) (Den.).
8. U.N. Charter art. 1, ¶ 2.
9. Id. art. 55.
10. Declaration on the Granting of Independence to Colonial Countries and Peoples, G.A. Res. 1514 (XV), U.N. Doc. A/RES/1514(XV) (Dec. 14, 1960).
11. Id.
12. International Covenant on Economic, Social and Cultural Rights art. 1(1), Dec. 16, 1966, 993 U.N.T.S. 3; International Covenant on Civil and Political Rights art. 1(1), Dec. 16, 1966, 999 U.N.T.S. 171.
13. ICESCR art. 1(2); ICCPR art. 1(2).
14. East Timor (Port. v. Austl.), Judgment, 1995 I.C.J. Rep. 90, ¶ 29 (June 30).
15. Id.
16. Declaration on Principles of International Law Concerning Friendly Relations and Co-operation Among States in Accordance with the Charter of the United Nations, G.A. Res. 2625 (XXV), U.N. Doc. A/RES/2625(XXV) (Oct. 24, 1970).
17. See Antonio Cassese, Self-Determination of Peoples: A Legal Reappraisal 140-41 (1995).
18. Act on Greenland Self-Government § 1, Act No. 473 (June 12, 2009) (Den.).
19. Id. §§ 2-8.
20. Id. § 21; Who Owns Greenland?, Chatham House (Jan. 8, 2026), https://www.chathamhouse.org/2026/01/who-owns-greenland.
21. Agreement Relating to the Defense of Greenland, U.S.-Den., Apr. 27, 1951, 2 U.S.T. 1485; Agreement to Amend and Supplement the Agreement Relating to the Defense of Greenland, U.S.-Den., Aug. 6, 2004, T.I.A.S. No. 04-806.
22. U.N. Charter art. 2, ¶ 4.
23. Armed Activities on the Territory of the Congo (Dem. Rep. Congo v. Uganda), Judgment, 2005 I.C.J. Rep. 168, ¶ 153 (Dec. 19).
24. S.C. Res. 242, ¶ 1(i), U.N. Doc. S/RES/242 (Nov. 22, 1967).
25. Annexation Is a Flagrant Violation of International Law, Says UN Human Rights Expert, Office of the High Commissioner for Human Rights (June 19, 2019), https://www.ohchr.org/en/press-releases/2019/06/annexation-flagrant-violation-international-law-says-un-human-rights-expert.
26. Id.
27. Declaration on Principles of International Law Concerning Friendly Relations and Co-operation Among States, G.A. Res. 2625 (XXV), U.N. Doc. A/RES/2625(XXV) (Oct. 24, 1970).
28. See Albrecht Randelzhofer & Oliver Dörr, Article 2(4), in 1 The Charter of the United Nations: A Commentary 200, 208-10 (Bruno Simma et al. eds., 3d ed. 2012).
29. Declaration on Friendly Relations, supra note 30.
30. G.A. Res. 68/262, U.N. Doc. A/RES/68/262 (Mar. 27, 2014).
31. Annexation Is a Flagrant Violation, supra note 28.
32. Vienna Convention on the Law of Treaties art. 52, May 23, 1969, 1155 U.N.T.S. 331.
33. Trump’s Greenland ‘Framework’ Deal, supra note 6.
34. Id.
35. Id.
36. See Malcolm N. Shaw, Title to Territory in Africa: International Legal Issues 26-29 (1986).
37. See Island of Palmas (Neth. v. U.S.), 2 R.I.A.A. 829, 839-46 (Perm. Ct. Arb. 1928).
38. Acquisition and Transfer of Territorial Sovereignty, Law Explores (May 4, 2018), https://lawexplores.com/acquisition-and-transfer-of-territorial-sovereignty/.
39. Id.
40. See Proposed United States Acquisition of Greenland*, Wikipedia, https://en.wikipedia.org/wiki/Proposed_United_States_acquisition_of_Greenland (last visited Jan. 31, 2026).
41. U.N. Charter art. 2, ¶ 4.
42. Craig Forcese, Acquisition of Territory and International Law, Legal Clarity (Jan. 11, 2025), https://craigforcese.substack.com/p/acquisition-of-territory-and-international.
43. Declaration on the Granting of Independence to Colonial Countries and Peoples, G.A. Res. 1514 (XV), U.N. Doc. A/RES/1514(XV) (Dec. 14, 1960).
44. Declaration on Friendly Relations, supra note 30.
45. Id.
46. Frontier Dispute (Burkina Faso v. Mali), Judgment, 1986 I.C.J. Rep. 554, ¶¶ 20-26 (Dec. 22).
47. Id.
48. See ICESCR art. 1; ICCPR art. 1.
49. Western Sahara, Advisory Opinion, 1975 I.C.J. Rep. 12 (Oct. 16).
50. Id. ¶¶ 79-162.
51. How Does Denmark Legally Own Greenland?, Legal Clarity (Aug. 29, 2025), https://legalclarity.org/how-does-denmark-legally-own-greenland/.
52. Id.; Act on Greenland Self-Government § 1, supra note 21.
53. Trump’s Greenland ‘Framework’ Deal, supra note 6.
54. Act on Greenland Self-Government § 1, supra note 21.
55. Sanger & Erlanger, supra note 4.
56. Act on Greenland Self-Government § 21, supra note 21.
57. Trump’s Greenland ‘Framework’ Deal, supra note 6; U.N. Charter art. 2, ¶ 4.
58. Vienna Convention on the Law of Treaties art. 52, supra note 35.
59. Sanger & Erlanger, supra note 4.
60. See Proposed United States Acquisition of Greenland, supra note 43.
61. See Shaw, supra note 39, at 26-29.
62. Act on Greenland Self-Government § 1, supra note 21.
63. Id. § 21.
64. See Sanger & Erlanger, supra note 4 (discussing potential security arrangements).
65. Agreement Relating to the Defense of Greenland, supra note 24; Agreement to Amend and Supplement the Agreement Relating to the Defense of Greenland, supra note 24.
66. Act on Greenland Self-Government § 1, supra note 21.
67. Id.; ICESCR art. 1; ICCPR art. 1.
68. U.N. Charter art. 2, ¶ 4; Declaration on Friendly Relations, supra note 30.
69. Trump’s Greenland ‘Framework’ Deal, supra note 6.
70. Vienna Convention on the Law of Treaties art. 52, supra note 35.
71. Declaration on the Granting of Independence to Colonial Countries and Peoples, supra note 46.
72. See Sanger & Erlanger, supra note 1; Annexation Is a Flagrant Violation, supra note 28.