By Isaac Christopher Lubogo
Abstract
Discourse surrounding the possibility of United States acquisition of Greenland—popularly associated with public statements made by United States President Donald J. Trump—has revived an anachronistic conception of territorial sovereignty reminiscent of nineteenth-century imperial practice. This article interrogates the legal, institutional, and geopolitical implications of such a proposition under contemporary international law. It examines two hypothetical acquisition pathways—military takeover and territorial buy-out—and evaluates their legality, feasibility, and consequences for Danish sovereignty, Greenlandic self-determination, and the integrity of the North Atlantic Treaty Organization (NATO). The article argues that neither military coercion nor transactional purchase offers a lawful or sustainable pathway to sovereignty over Greenland, and that any such attempt would fundamentally undermine the rules-based international order and destabilize collective security arrangements.
I. Introduction: The Resurrection of an Obsolete Imperial Logic
The proposition that a modern state may acquire territory through force or financial purchase evokes a bygone era of imperial expansion—an era largely repudiated by the post-1945 international legal order. When United States President Donald J. Trump publicly entertained the idea that the United States could “buy” Greenland, the proposal was widely interpreted as provocative rather than programmatic. Yet the persistence of the debate, and its continued resonance within contemporary strategic discourse, warrants serious legal examination, particularly in light of Greenland’s growing strategic importance in the Arctic and its unique constitutional relationship with the Kingdom of Denmark.
This article proceeds from the premise that power alone no longer legitimizes territorial acquisition. Sovereignty in contemporary international law is mediated through binding norms of self-determination, consent, and collective security, all of which impose strict legal constraints on state behavior. The Greenland question therefore provides a critical case study for testing the resilience of these norms in an era of renewed great-power competition and executive-driven geopolitical assertion.
II. The Legal Status of Greenland
Greenland is an autonomous territory within the Kingdom of Denmark, governed under the Greenland Self-Government Act of 2009. While Greenland exercises extensive authority over internal affairs, defence, foreign relations, and security remain—by constitutional allocation—within the competence of the Danish state. Denmark is, in turn, a founding member of the North Atlantic Treaty Organization.
Critically, Greenland possesses a recognized right to self-determination under international law, including the right to pursue independence through democratic and lawful means. However, until such independence is validly achieved, Greenland remains an integral part of Danish sovereign territory and benefits from the legal and security protections flowing from Denmark’s international obligations, including NATO membership.
III. Military Takeover of Greenland: Illegality and Alliance Collapse
A. Prohibition of the Use of Force
A military seizure of Greenland by the United States would constitute a manifest violation of Article 2(4) of the United Nations Charter, which prohibits the threat or use of force against the territorial integrity or political independence of any state. No recognized exception—whether self-defence, consent, or humanitarian intervention—could plausibly justify such an action.
Under customary international law, such conduct would amount to aggression, resulting in an illegal occupation. The legal consequences would include state responsibility, exposure to international countermeasures, and near-universal condemnation, thereby placing the United States in direct breach of the international legal order it historically helped to construct.
B. NATO Implications and the Article 5 Paradox
Because Greenland constitutes Danish territory, any armed attack upon it would legally amount to an armed attack on Denmark, thereby triggering Article 5 of the North Atlantic Treaty. NATO members would, as a matter of treaty obligation, be required to respond.
This produces an unprecedented paradox within collective security law: NATO would be legally compelled to confront aggression committed by its most powerful member. Either response—collective defence against the United States or institutional inaction—would fatally undermine NATO’s credibility. In practical terms, such a scenario would likely precipitate Denmark’s withdrawal from NATO, institutional paralysis or fragmentation within the alliance, and the collapse of the post-war European security architecture.
C. Greenland’s NATO Status Post-Occupation
Greenland is not itself a NATO member; its protection derives exclusively from Denmark’s membership. Under United States military occupation, Greenland would fall outside NATO’s collective defence framework, relying solely on unilateral U.S. security guarantees. Paradoxically, military takeover would therefore diminish rather than enhance Greenland’s multilateral security position.
IV. Territorial Buy-Out: The Myth of Lawful Purchase
A. The Obsolescence of Territorial Sales
Although historical precedents such as the Louisiana and Alaska purchases exist, contemporary international law rejects the commodification of territory and peoples. Today, a lawful transfer of territory requires:
(1) the consent of the sovereign state;
(2) the free and informed consent of the affected population; and
(3) full respect for the right to self-determination.
Denmark has unequivocally rejected any sale of Greenland, and Greenlandic authorities have similarly repudiated the notion of being transferred or purchased. Absent these consents, any attempted territorial buy-out would be legally void.
B. Self-Determination as a Peremptory Norm
The right of peoples to self-determination occupies a foundational position within the international legal order and is widely understood to possess peremptory normative force. Greenland cannot be transferred between sovereigns without the express and democratically articulated will of its population. The United States cannot lawfully “purchase” Greenland from Denmark over the heads of Greenlanders.
The only lawful pathway would involve Greenland first achieving independence through democratic processes, followed by treaty-based alignment or association with the United States. Such a process would constitute state formation and voluntary association, not territorial acquisition.
V. NATO Consequences of Greenlandic Separation
Three legally distinct scenarios merit consideration.
First, if Greenland were to become United States territory, NATO would not apply. The alliance does not extend collective defence guarantees to internal territories of member states.
Second, if Greenland became independent and aligned with the United States, NATO membership would require formal application and unanimous consent. Admission would be uncertain and potentially subject to veto.
Third, if Greenland remains within Denmark, existing NATO protections and lawful U.S. basing arrangements continue without disruption.
The strategic irony is evident: separation from Denmark risks weakening Greenland’s security posture rather than strengthening it.
VI. Strategic Reality: Influence Without Sovereignty
The United States already enjoys extensive strategic benefits in Greenland through lawful means, including long-standing military basing rights and advanced intelligence infrastructure. These advantages have been secured without sovereignty transfer, through treaties and alliance cooperation. Any attempt at acquisition would yield marginal strategic gains at disproportionate legal, diplomatic, and institutional cost.
VII. Conclusion: Power Constrained by Law
The Greenland question underscores a central truth of contemporary international law: power no longer legitimizes possession. Neither military coercion nor financial inducement can lawfully transfer territory in defiance of sovereignty, self-determination, and collective security norms.
A military takeover would constitute illegal aggression and likely precipitate the collapse of NATO. A forced buy-out would violate peremptory norms of international law. The only lawful pathway—Greenlandic independence followed by voluntary treaty association—is complex, uncertain, and dependent on democratic consent.
Ultimately, Greenland is not a commodity, NATO is not expendable, and legitimacy cannot be manufactured through force. Any attempt to resurrect imperial modes of acquisition would not signal strength, but a profound retreat from the rule of law in international relations.
