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Secession and the EU: Brave New World or Continuation of Membership?

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About The Author

Kristiyan Stoyanov (Guest Contributor)

Krisityan is an MJur candidate in International Trade and Comparative Law at Durham Law School. Over the years, Krisityan has obtained legal work experience from different law firms as well as attended a number of Open Days. Outside of law, he is interested in history, politics, international relations and promoting diversity. He also enjoys travelling, hiking and swimming.

© Liz Castro

There's no alternative to Catalan independence.

Carles Puigdemont

One of the common features of Flanders in Belgium, Catalonia and the Basque Country in Spain, Brittany in France, and Sicily and Corsica in Italy, is that these Western European regions all contain highly active pro-secessionist movements. As articulated by Professor Christakis, secession involves:

[T]he unilateral withdrawal from a state of part of its territory and population with the will to create a new state.

A key question that arises in the event of secession is whether the international obligations binding the mother state will continue to apply in the new seceded state. Accordingly, if any of the regions cited above – all of which are EU Member States – ever secedes from its mother state, then people will inevitably wonder whether the newly independent state will also automatically become a member of the European Union.

This article argues that if a region in the EU secedes from its mother state, it could hardly enjoy continued access to the EU under EU law. The position is not much different under public international law; in the absence of strong political support at the EU level, the new state is likely to face enormous difficulties in proving that international law provides a right to continued membership.

Legality of secession

International law, and the international community accordingly, have taken a rather neutral position on secession. With the view of allowing easy manoeuvring within this extremely political area, a case-by-case basis has been adopted. For instance, following the bloody internal conflicts in the former Yugoslavian Republic, in Accordance with International Law of the Unilateral Declaration of Independence In Respect of Kosovo [2010], the International Court of Justice ruled that Kosovo’s declaration of independence was not in violation of international law. However, as well as strictly ruling on the facts of the case and not forming any guidelines from which future cases could apply this precedent, Kosovo’s case remains controversial because it has not been recognised by the international community, with the current political climate appearing not to be in its favour.

In contrast, the South Sudan application to the UN, and secession from Sudan, was unilaterally endorsed in 2011. An argument advanced among academics is that the Sudanese secession differs from the Kosovo secession as the mother state in the former case recognised the secession. However, in practice, it makes little difference whether the mother state recognises the new entity as, according to the Montevideo Convention 1936, this is not a requirement.

Secession was also considered in the case of Reference re Secession of Quebec [1998], in which the Canadian Supreme Court ruled that the secession of Quebec could be recognised only if it had received enough support in a referendum.  However, the Quebec case is unlikely to form a workable precedent because it has not been tested on any level due to the Quebecois voting against independence. Moreover, the Court’s reasoning merely referred to national law and that the results would have been recognised on a national level; this does not mean that it would have had the same outcome on an international level.

Thus, on an international level, the legality of secession is still an issue with no uniform answer. While there might be some examples, such as the secessions of Abkhazia, South Ossetia, and Kosovo, the issue is still ongoing and appears to have no general criteria.

Continued Membership of the EU under EU Law

Article 48 of the Treaty on European Union (TEU) governs the procedure used to amend the EU Treaties. According to the official position of the Scottish Government in 2013, through this procedure a seceded territory may be afforded continued EU membership and so fall within the ambit of Article 52 TEU, which lists the countries to which the EU treaties apply.

As both the TEU and the Treaty on the Functioning of the European Union (TFEU) apply to the territories of the 28 Member States currently listed under Article 52 TEU, the Scottish Government argues that any newly independent territory will be deemed to have passed the necessary Article 49 TEU application when it became an EU member with its former parent state. In other words, the membership status of the seceded region has already been fixed by virtue of the previous ratification of the EU Treaties by its former parent state. The Scottish Government states that the fact that a territory is leaving its mother state does not change this position.

On the one hand, it is true that the Treaties’ scope encompass only the Contracting Parties, which do not include their former territories. But on the other, only a literal reading of Article 52 TEU leads to the conclusion that the Treaties only apply to the territories that are under the control of the MS, but not that they continue to include those territories that were subject to EU law by the Treaties on the day that the mother state gave effect to EU law.

Nevertheless, the arguments of the Scottish Government remain flawed. The problem with arguing that Article 48 TEU - rather than Article 49 TEU - is the correct legal basis is in the divergent purposes that those two Articles serve. The latter governs the accession of a country to the EU, requiring a country to fulfil numerous requirements before it joins the EU. From this, it follows that a seceded territory would have to be reviewed in front of the ‘Copenhagen Criteria’ in the same way as a third country, in order to achieve accession to the EU.

The Copenhagen Criteria spells out the requirements that a candidate country must fulfil in order to join the EU. These requirements are:

  1. Stability of institutions guaranteeing democracy, the rule of law, human rights and respect for and protection of minorities;
  2. A functioning market economy and the ability to cope with competitive pressure and market forces within the EU; and
  3. Ability to take on the obligations of membership, including the capacity to effectively implement the rules, standards and policies that make up the body of EU law (the 'acquis'), and adherence to the aims of political, economic and monetary union.

While it is unlikely that the newly independent territory would fail to meet the criteria, it would not be fair to give preferential treatment to one state, and so a review must occur. After all, while there are few doubts that a potential candidate such as Iceland will easily meet the Copenhagen criteria, the Article 49 TEU procedure must still be followed. As such, the same rules must apply to any seceded territory.

The second basis for arguing that Article 48 TEU is not the correct provision is because its functioning is limited to the affairs that arise among the current Member States, and accepting a new Member State to the EU would not fall within the scope of Article 48 TEU. Some have pointed to the German reunification in 1990, where the then EEC allowed East Germany to be a member of the EU without having to be subject to any further requirements. However, the difference here is that Germany simply acquired new territory; a new sovereign state was not formed. Consequently, there was no reason for the EEC to re-examine Germany’s application because the main State was still there.

Thirdly, from a purely practical point, using Article 48 TEU to accommodate the new state would be extremely cumbersome. The new state would lack authority to initiate the process and so this could only be done by the European Commission, European Parliament, or a MS. Moreover, as only current MSs can be party to the Article 48 TEU process, the new state would require representation by another state, which could be its former parent state. On top of that, this reform would require unanimity – this, due to the national law of some MSs, would be subject to national referendums.

Access to the EU by virtue of Public International Law

According to Article 34 of the Vienna Convention on Succession of States (VCSS) in respect of Treaties 1978:

When a part or parts of a territory of a State separate to form one or more States…:

  • any treaty in force at the date of the succession of States in respect of the entire territory of the predecessor State continues in force in respect of each successor State so formed;
  • any treaty in force at the date of the succession of States in respect only of that part of the territory of the predecessor State which has become a successor State continues in force in respect of that successor State alone.

In addition, Article 35 provides:

When, after separation of any part of the territory of a State, the predecessor State continues to exist, any treaty which at the date of the succession of States was in force in respect of the predecessor State continues in force in respect of its remaining territory…

Although only 5 EU Member States (Cyprus, Czech Republic, Estonia, Slovakia and Slovenia) have ratified the VCSS, and it cannot be regarded as codification of customary international law, as argued by Professor Aust in Modern Treaty Law and Practice, recent state practice has gradually evolved in line with the Convention’s provisions.

If this is then continued to be followed in practice, this would mean that the newly formed state may be legally bound by the obligations which stem from the EU Treaties. If the newly independent state has to continue with these obligations, it must accordingly remain part of the EU. Otherwise, it would be illogical to require a non-EU territory to comply with EU law.

Moreover, as argued by de Roux, due to the fact that the successor entity has already accepted the responsibilities that followed from the parent State’s legal commitments, the former must continue with these obligations. In other words, if for instance Catalonia secedes from Spain, it will have to remain a member of the EU because the Catalan community has also enabled the direct effect to EU law on the day on which Spain ratified the EU accession agreement.

However, the weakness in de Roux’s proposition is that it could only apply to regions that were required under national law to give their consent to the ratification of the EU Treaties (e.g. the Flanders region in Belgium).

Article 34 VCLT

The direct application of Article 34 Vienna Convention on the law of treaties 1969 (VCLT) within the EU context would mean that neither the TEU nor TFEU could impose obligations on the newly proclaimed state, unless that state gave its consent. Article 34 VCTL states:

A treaty does not create either obligations or rights for a third State without its consent.

However, separatist movements in the EU are unlikely to advocate an anti-EU position as they strongly desire to remain as close as possible to the Union. The result would likely be that the newly independent state would have access to the EU because it, first, wishes to do so, and second, as opined by Professors Chamon and Van der Loo, there is a presumption stemming from Article 34 VCLT that favours a continuation of membership.

In substance, Article 34 imposes a negative obligation by allowing the application of only those Treaties that the state has ratified. Consequently, if the newly independent state has given its consent to the Treaties to which the mother state was a contracting party, there is nothing to prevent the newly independent state from succeeding the Treaty’s obligation; the VCLT essentially prohibits undesired obligation(s) while here it is desired and the VCSS Article 16 leaves this loophole unclosed.

Article 4 VCSS

The above considerations, however, could be challenged by the text of Article 4 VCSS, which reads as follows:

The present Convention applies to the effects of a succession of States in respect of:

  • any treaty which is the constituent instrument of an international organization without prejudice to the rules concerning acquisition of membership and without prejudice to any other relevant rules of the organization...

However, in practice, Article 4 VCSS does not do anything more than refer back the issue to the international organisation and its relevant Treaty. As EU law does not tell us anything about secession, in the absence of an answer it is possible that the new state may be able to rely on VCSS Articles 34 and 35.

If we proceed on the assumption that the seceded state would automatically be considered part of the EU due to its previous ties with its mother State, this reliance on the VCSS would not prejudice the EU’s accession procedure as no new state would need accession. In other words, the newly seceded State is not a new State to affect the ‘rules concerning acquisition of membership’, as spelled out in Article 4 VCSS 1978, because it will not constitute a new membership, but a continuation of an old one. This differs with accession of a new country because in this case the new territory is annexed to the EU, whereas in the case of secession it has already been annexed.

In Articles 34(2)(a)(b) and 35(a)(b)(c) VCSS 1978, we can see the exceptions of Article 34, which would apply when the purposes of the newly independent state substantially differ from its predecessor. However, if the newly independent state’s regime does not differ from its predecessor state, it is argued that there should be nothing to prohibit it from continuing its membership in the EU.


However, the above arguments are largely theoretical as the majority of EU states have not yet ratified the VCSS, nor is the EU a Contracting Party to the convention; whereas it has been seen as getting closer to forming part of customary international law, this is debatable. Whilst the VCLT, on the other hand, might be seen as customary law, it plays a marginal role to the discussion here.

Therefore, it follows that public international law does not provide a clear answer to this issue. As such, the answer would ultimately fall on many political considerations. However, if the EU takes a purely public international law perception then there might be a basis to allow the newly seceded state to remain part of the EU.

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Tagged: Constitution, European Union

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