Between Principle and Presumption: The ILC’s Missed Opportunity in Its Sea-Level Rise Report
Inji Mammadli
Introduction
The International Law Commission (ILC) recently adopted its report on sea-level rise in relation to international law, marking a significant milestone in addressing one of the most pressing challenges facing the international legal order. This report tackles critical issues such as the continuity of statehood amid territorial losses caused by rising seas—a matter which is, naturally, of profound significance for vulnerable island states whose very existence is threatened. However, a careful analysis reveals notable differences between this final report and the consolidated report previously prepared by the co-chairs. Among the most contentious issues is whether the continuity of statehood can be described as either ‘a principle of continuity of statehood’ or ‘a presumption of continuity of statehood’ that would apply when a state’s territory is affected by sea-level rise. The Commission ultimately avoided both formulations, opting instead for the more neutral term ‘support’ for the continuity of statehood.
This analysis advances the contention that ‘principle’ constitutes the most appropriate characterisation in this context, notwithstanding the Commission’s apparent reluctance to adopt such terminology. Moreover, it will be demonstrated that certain formulations within the report itself, while ostensibly neutral, implicitly affirm the normative character of the continuity of statehood in a manner more consonant with ‘principle’ than alternative conceptualisations.
The Conspicuous Absence of Terminology in the Final Report
Perhaps the most striking feature of the Final Report is what it does not contain. The terms “presumption” or “presume(d)” are entirely absent from the document. Equally notable is the absence of “principle” in discussions regarding the continuity of statehood. This is rather striking given that the Final Consolidated Report of the Co-Chairs of the Study Group on sea-level rise in relation to international law explicitly employed both the term ‘presumption’ (paras 41, 162) and the term ‘principle’ (para 151). This deliberate omission speaks volumes about the Commission’s hesitancy to commit to a definitive characterisation of the continuity of statehood in the face of territorial challenges posed by rising sea levels.
The absence of these terms is not due to oversight but follows extensive deliberations within the Commission. States also expressed divergent views in the Sixth Committee on the appropriate terminology, with some advocating for “presumption” (see here, here, here, here and here) while others favoured “principle”(see here, here, here and here). This divergence is also reflected in key regional declarations: the 2023 Pacific Islands Forum Declaration on the Continuity of Statehood and the Protection of Persons in the Face of Climate Change-Related Sea-Level Rise employs “presumption” (paras 8, 12), whereas the more recent 2024 Alliance of Small Island States (AOSIS) Declaration adopts “principle” (para 1). Given these differing positions, the ILC was uniquely positioned to take a firm stance on which term more accurately reflects international law. Indeed, according to the mandate, the Study Group was specifically asked to examine the “possible legal effects on the continuity or loss of statehood” (para 16(a)) and even legal fictions (para 16(c)). These questions essentially required the ILC to confront the baseline question: does international law contain a principle of continuity, a presumption of continuity, or neither? It is, therefore, rather disappointing that the Commission ultimately shied away from this responsibility. Instead of choosing between ‘presumption’ and ‘principle,’ the Commission opted for what it perceived as a neutral alternative: ‘support’ for continuity (para 39 of the Final Report). This linguistic compromise effectively sidesteps the substantive debate between competing characterisations. By adopting this neutral phrasing, however, the ILC has unfortunately missed an opportunity to advance legal clarity on an issue where precision matters immensely.
The Case for “Principle”
Upon prima facie examination, the Commission's reluctance to designate the continuity of statehood without territory as a 'principle' is scarcely surprising.
The characterisation of a norm as a general principle of law necessitates recognition by the community of nations (see ILC’s Draft Conclusions on General Principles of Law, Conclusion 2). The methodological framework for identifying such principles demands a comprehensive assessment of all available evidence demonstrating such recognition. An examination of comments from states and observable state practice reveals an absence of sufficient evidence that states collectively conceptualise continuity of statehood as a principle per se. On the contrary, certain states, such as Germany, have articulated explicit opposition to such characterisation, arguing instead that ‘presumption’ is better suited to address the issue, since it avoids making claims about the status of continuity. However, this argument prioritises taxonomical precision over practical effect.
One can also not concur with Germany’s contention that “[t]o assume that there is a principle of continuity of statehood, which implies unlimited continuity, appears to be contradicted by the historical fact that states have ceased to exist” (para 11). This argument misapprehends the nature of historical state extinctions. An examination of the historical record demonstrates that every documented instance of a state “ceasing to exist” has been predicated upon a consensual, collective determination—whether executed through constitutional mechanisms or negotiated agreements (as involuntary state extinction by external circumstances is without precedent; see here). The dissolution of the Union of Soviet Socialist Republics, for instance, materialised pursuant to declarations by constituent republics and the Belavezha Accords concluded among Russia, Ukraine, and Belarus. Similarly, Czechoslovakia’s dissolution proceeded through legislative action, with the Federal Assembly enacting legislation to formally terminate the federation.
The Commission itself acknowledged this when it maintained that continuity of statehood cannot be denied except upon consent by the state concerned (para 39 of the Final Report). This phrasing serves a dual function in this context. Primarily, it reaffirms that statehood continuity operates as the default legal position—once statehood is established, it persists notwithstanding transformations in territory, population, or governmental structure. This formulation confirms that no state possesses the authority to extinguish another’s statehood. Secondarily, it appears to articulate a separate “extinction-by-consent” rule, whereby a state retains the prerogative to terminate its own existence through appropriate constitutional processes.
Consequently, should a low-lying state ever elect to “terminate” its statehood rather than e.g. establish a government-in-exile, it could effectuate this choice through internal constitutional procedures coupled with an appropriate international instrument. Absent such consensual determination, no state or group of states could legitimately deprive it of statehood merely because its physical territory has submerged beneath rising waters. Thus, contrary to Germany’s assertion, the principle of continuity does not imply unlimited continuity irrespective of circumstances; rather, it safeguards states against involuntary extinction—precisely the scenario confronting low-lying island nations threatened by sea-level rise.
Thus, the ILC’s position aligns more closely with a principle than a presumption, as it establishes a norm that cannot be unilaterally overridden by external actors. When a legal concept can only be negated through explicit consent, it bears the hallmarks of a principle rather than a mere presumption. Principles in international law typically carry normative weight derived from widespread state practice and the fundamental structure of the international legal order, which values stability and the sovereign equality of states. Conversely, presumptions lack the legal weight necessary to protect vulnerable states against the unprecedented challenges posed by climate change and sea-level rise. Thus, the term ‘presumption’ carries significant disadvantages in this context. By definition, presumptions can be rebutted. Characterising continuity of statehood as a presumption could therefore suggest that external actors might overcome this presumption through evidence or argument—a dangerous proposition for small island states.
Moreover, framing continuity as a presumption unfairly places the burden on affected island states to defend their continued statehood. This approach contradicts the established understanding that once statehood is achieved, its continuation is not contingent on maintaining the criteria that led to its initial recognition. In other words, from the perspective of affected states, the Montevideo Convention criteria establish requirements for the creation of statehood but do not automatically reverse statehood when those characteristics diminish or disappear. Statehood, once achieved, functions as a one-way door—easier to enter than to exit. This understanding supports treating continuity as a principle rather than a rebuttable presumption.
Conclusion
The ILC’s reluctance to choose between “principle” and “presumption”, while reasonable to some extent, is still disappointing. By selecting the neutral term “support,” the Commission, to all appearances, sacrificed clarity for institutional comfort. For island states existentially affected by sea-level rise, however, this is not merely an academic or a semantic caution. In this critical moment, where words shape the fate of nations, the ILC’s terminological ambivalence ostensibly betrayed an institutional reluctance to provide the vulnerable states the legal certainty they required in the face of existential climate threats. Nevertheless, despite the Commission’s hesitancy to adopt definitive language, this paper maintains that the principle of continuity of statehood continues to exist.
Author
Inji Mammadli is a PhD Candidate at Trinity College Dublin's School of Law. Her research discusses options to preserve the statehood of small island states threatened by the effects of climate change. She has assisted the work of the Presidency of the UN Climate Conference in Baku in 2024, as well as that of the International Law Commission during its 76th session. Inji is currently a teaching assistant in public international law.
