Two Tensions: How International Law Fails to Properly Address Secession

Even in seemingly stable political communities such as the EU or the UK, secessionist movements regularly put forward their claims for independence. This poses a challenge for both constitutional and international law. The first challenge is that state creation is both political and legal. No right to self-determination or secession – even if it exists, which in most cases it does not – relieves a separatist movement of the duty to make and sustain their case politically. The second challenge is rooted the current substance of international law on secession. In 2022, the UK Supreme Court found that international law does not help Scotland’s case for independence. This illustrates the argument that international law on its own is not the main legal space in which secessionist pressures find accommodation. On the contrary, constitutional arrangements currently seem more important than international law.Constitutional law may ultimately also prove more fruitful in accommodating political tensions about territory than international law currently does or will do in the foreseeable future. These two challenges are identified in and shape the recently published Research Handbook on Secession (Edward Elgar 2022).

Law and Politics

Secession as defined in the introduction of the Research Handbook is “the emergence of a new state in a part of the metropolitan territory of an existing state” (p. 1). The metropolitan state claims the territory in question as its own and the secessionist movement or group does the same. This results in competing territorial claims and a secession or the lack thereof is in a sense a decision as to which of these claims prevails. Competing claims and how to settle them is law’s bread and butter. International law in this case does this by neither allowing nor prohibiting secessions, and thus suggesting that it is neutral. But this narrative does not withstand scrutiny. Rather, international law privileges consensual secessions because it builds in extra-legal criteria of legitimacy. As we put it, again, in the Introduction:

First, consensual secessions are more likely to succeed both legally and politically. Legally, they are more likely to succeed because the required displacement of a competing claim to territorial integrity is already built into their consensual nature. Politically, consent from the parent state usually indicates that the work of legitimising and sustaining a secessionist claim has already been done. Second, consensual secessions are more likely to be legitimate over and above their legality and their likely success, as the consent of a parent state can be regarded as the democratic counterweight to the self-determination of the secessionist entity. Third, and relating to both the previous points, consensual secessions are less likely to depend on recognition by other existing states to be successful. This is because the potential constitutive character of such recognition only really needs to be contemplated for unilateral secessions. (p. 4)

This illustrates that consent from the metropolitan state is the primary path to independence. The UK Supreme Court’s judgment that the UK constitution indeed provides for such consent to be required domestically can thus be seen as an expression of the international law on the matter (analysis here and here).

Privileging consensual secession is not as such problematic, of course. What is problematic is to privilege it without also providing ways of settling competition when agreement is unlikely or impossible. Making it difficult for unilateral secession to occur – which is what international law currently does – is not the same as providing avenues for settlement. It is rather like the law saying that it will not provide for adjudication until the parties of a contract can agree what the terms of the contract are. It is this failure of international law to embrace situations where consent from the metropolitan state is not forthcoming that makes secessions politically fraught because it requires of the secessionist movement to build a strong and legitimate case but does not do the same for the metropolitan state.

One might think that treating consent as the most valuable goal in secessionist processes is all things considered the best policy, but the considerable imbalance between metropolitan state and separatist groups would need to be addressed and justified much more explicitly than it currently is. As it stands, it may be trite to state that secessions are always both political and legal. What is perhaps less trite is to point out that the law here heightens the political stakes.

International and Constitutional Law

But perhaps the somewhat unfortunate role of international law is not (only) due to its content but also due to the fact that it is international law, rather than constitutional law. If it is true that state creation is a fundamentally political issue, this would not be surprising. Political self-determination is connected to democractic institutions (or the lack thereof) and these are primarily provided for and regulated by constitutions rather than the international legal order. The Research Handbook gives this possibility due weight by including several chapters that are written explicitly from a constitutional perspective: on Quebec (chapter 10), on Jordan and Palestine (chapter 17), on independence referendums (chapter 7), the constitutional aspects of the dissolution of Czechoslovakia (chapter 16), and – most topically – on Scotland (chapter 9) and Catalonia (chapters 12 and 13).

Whatever one’s view on these current examples, it is undeniable that constitutional arrangements are influential in determining how separatist claims are articulated and – ultimately – whether and how they are successful. In the Catalan case, the Spanish constitution and the findings of the Constitutional Court meant that the 2017 referendum could not generate legitimacy because it was unconstitutional. The arrangements in the UK known as devolution, and relating to Scotland based on the Scotland Act 1998, have now been determined by the UK Supreme Court to mean that Scotland too would follow a path of illegality if it were to try and hold another independence referendum with consent from the UK government.

Both the Scottish (analysis here) and Catalan movements relied to some extent on interpretations of the international law right of peoples to self-determination. But neither was successful at the constitutional level, which could be read as a redemption of the argument that at least some conceptualisations of this right are a trap and that international lawyers and separatists alike would do well to focus their attention and energy on constitutional law instead. As if to add further credence to this view, in applying the relevant international law norms, the UK Supreme Court (para 88) looked to the Supreme Court of Canada and its Quebec Reference, rather than to pronouncements of international bodies. The current trends in the legal practice thus embrace that international law is not the only space to make secessionist claims and that it is almost certainly not the most fruitful one.


Research Handbook on Secession
ed. by Jure Vidmar, Sarah McGibbon, and Lea Raible
Edward Elgar | Cheltenham, Northampton, 2022. 410 pp.

Written by

Lea Raible is Senior Lecturer in Public Law at the University of Glasgow School of Law. In 2022, she was a Guest Researcher at the Research Professorship "Global Constitutionalism" at the WZB.
Website at the University of Glasgow

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