In earlier posts (here and here) there was a discussion about the different scenarios that might play out following the UK’s vote to exit the European Union. These and other debates have focused largely on the legal implications for the UK and the European Union and the modalities of their future relationship. Yet the UK’s withdrawal from the Union will also have consequences at the international level, especially for the hundreds of international agreements concluded by EU and the UK with third states and international organizations. In this post I will look at some of the international law issues that arise from the UK’s exit from the European Union. The EU is a unique, perhaps even sui generis, international organization, but it is an international organization nevertheless and withdrawal will necessarily gives rise to questions under public international law. An important question in this regard is the fate of the international treaties to which the EU and the UK are party.
The first point of departure are the rules in the treaty establishing the international organization itself, that is, the EU Treaties. The Vienna Convention on the Law of Treaties (VCLT) establishes that a party may withdraw ‘in conformity with the provisions of the treaty’, which in this case is Article 50 of the Treaty on European Union (TEU). Once this has been invoked, the EU and the UK will negotiate an agreement setting out the arrangements for withdrawal. Some have argued that the UK might be able to ‘bypass’ Article 50 TEU using international law, by invoking the Brexit vote as a ‘fundamental change in circumstances’ according to Article 62(1)(a) VCLT. Such proposals should not be taken seriously. This article of the VCLT was deliberately worded negatively, stating that a fundamental change in circumstances cannot be invoked unless two restrictive conditions are fulfilled. These are: (a) the existence of those circumstances constituted an essential basis of the consent of the parties to be bound by the treaty; and (b) the effect of the change is radically to transform the extent of obligations still to be performed under the treaty. The International Court of Justice has moreover pointed out “the stability of treaty relations requires that the plea of fundamental change of circumstances be applied only in exceptional cases.” (Case concerning the Gabčíkovo-Nagymaros Project (Hungary/Slovakia) (Judgment)  ICJ Rep 7. para. 104) As Professor Kenneth Armstrong argues:
“there is simply no way that the European Court of Justice would permit the autonomous legal order of the European Union and the specific procedural mechanism of Article 50 TEU to bend to international law in this manner.”
While it is possible that avenues other than Article 50 may be used (for instance, to allow a form of ‘associate membership’) the EU Treaties provide a clear provision that covers the exit of a Member. Article 50 is silent, however, for the most part on the important issues that will face the UK, the EU and the many other states with whom they have legal relations.
There are few examples of states leaving international organizations, especially one with a well-developed legal order such as the European Union. One example of ‘withdrawal’ was Greenland. However, since Greenland was not an EU Member State in its own right, it was not technically possible for it to withdraw. Rather, Denmark sought to modify the territorial application of substantial parts of the Treaties to exclude EU law applying to Greenland. Special arrangements, such as those regarding fisheries and trade rights, were developed, and the Member States and institutions were consulted.
The European Union is a party to a large number of international treaties, ranging from trade and economic issues to human rights and the environment. One question that will arise relates to the fate of these international agreements and whether they will continue to apply to the UK as a non-EU Member State. These agreements will often include a clause specifying the territory on which they will apply. The EU Korea Framework Agreement sets out:
“This Agreement shall apply, on the one hand, to the territories in which the Treaty on European Union is applied and under the conditions laid down in that Treaty, and, on the other hand, to the territory of the Republic of Korea.” (Article 52)
Once the UK is no longer a member of the EU, such agreements will prima facie no longer apply in respect of the UK, since the UK will no longer be considered one of the territories on which the Treaty on European Union applies. Article 29 VCLT also sets out that a treaty is binding on a party in respect of its entire territory, which following withdrawal would no longer include the UK. In many cases, however, the UK and the other Member States are member of these agreements alongside the EU (so-called ‘mixed agreements’). For instance, the United Kingdom will continue to be a member of the World Trade Organization alongside the EU and the other EU Member States, but will have to negotiate the terms of its future membership outside the Union.
Complicated issues also arise in cases where there are ‘bilateral’ agreements between the EU and its Member States on the one hand and a state or group of states on the other. The Cotonou Agreement for example, involves the EU and the Member States as well as 79 countries from Africa, the Caribbean and the Pacific, yet it is structured as a bilateral treaty. The UK may wish to withdraw also from these agreements in order to develop its own trade relationships with these countries. Upon withdrawal, the UK and the Union will likely have to inform their treaty partners about the change in status of the UK. In some cases this may require consent of the third states, and a separate protocol to address this change in status may have to be adopted.
Yet another issue is the fate of so-called ‘EU-only’ agreements. These are agreements concluded by the EU but the EU Member States are not parties to the agreement. This occurs, for instance, with agreements in the field of EU Foreign and Security Policy or where the EU has exclusive competence, such as agreements in the field of maritime resources. It is unclear whether such ‘EU-only’ agreements would continue to apply to the UK after withdrawal. An agreement entered into by the EU is binding on EU Member States by virtue of EU law, specifically Art. 216(2) TFEU. Yet if the EU Treaties no longer apply to the territory of that state, one could argue that the international agreement no longer applies in respect of that territory. Since the EU is as a separate and distinct legal entity under international law, the UK should not be bound by the obligations of an organization from which it has withdrawn. An alternate view is that the UK would continue to be bound by the obligations entered into by the EU by way of succession. The EU, it could be argued, was really exercising powers to conclude a treaty on behalf of the Member States, including the UK. Therefore the leaving Member State would continue to be bound by EU’s obligations upon withdrawal. While the Court of Justice of the EU has found that the Union may under certain circumstances be the successor of obligations of the EU Member States (Judgment in International Fruit Company and Others v Produktschap voor Groenten en Fruit, Joined Cases 21 to 25/72, EU:C:1972:115, para. 7) it is not clear that obligations could flow in the opposite direction. The former view, that the UK would not continue to be bound, is probably the most legally accurate. However, this would allow a state to withdraw from its international obligations with a third state simply by leaving an international organization, without the consent of that third state. This would be problematic in terms of legal certainty and stability in the UK’s treaty relationships. This shows how the UK’s decision to leave the Union not only affects the relationship between the UK and the EU, but also has wider ramifications for a number of international parties.
Many of these issues may be dealt with in part by the agreement negotiated between the UK and the Union. They may decide, for instance, that these agreements will continue to apply with respect for the United Kingdom for a specific period during which the UK can decide whether to remain bound by these agreements. While such agreement can address these issues, there are unlikely capable of addressing everything and unforeseen questions will arise. In this case, international law, and the law of treaties may come into play. The UK is a party to the 1969 VCLT and the Court of Justice of the European Union has stressed that the provisions of the VCLT apply to the EU by virtue of customary international law. For instance, the principle of pacta tertiis nec nocent nec prosunt (‘a treaty binds the parties and only the parties; it does not create obligations for a third state’) enshrined in Art. 34 VCLT is a principle of customary international law binding on the Union (Judgment in Brita v Hauptzollamt Hamburg Hafen, C-386/08, EU:C:2010:91, paras 40–45). This means that an EU-UK agreement on these issues would not be capable of binding third states without their consent.
The UK, the EU and the EU Member States now enter a period of uncertainty. This uncertainty also applies to the many third states and organizations with which the EU and the UK have significant legal relationships. Like many other important questions, these issues were largely ignored during the referendum debate. In addition to the myriad of other legal issues that will arise under EU law and the law of the UK, further compilations arise under international law.