Can the EU Expel a Member State? The Constitutional Limits of European Integration

The European Union is founded on a set of values that its member states are expected to respect, including democracy, the rule of law, human dignity and the protection of human rights. These commitments are not merely political declarations. They are embedded in Article 2 of the Treaty on European Union (TEU) and underpin the legal and institutional framework through which the Union operates. Membership therefore involves more than participation in a common market or access to the benefits of European integration; it also entails a commitment to a shared constitutional order.

Yet the European treaties contain an apparent asymmetry. They establish a procedure through which a state may voluntarily withdraw from the Union under Article 50 TEU, and they provide mechanisms to address serious breaches of the Union’s fundamental values under Article 7 TEU. They do not, however, expressly provide for the involuntary expulsion of a member state, even in circumstances where that state persistently undermines democracy or the rule of law.

This omission is more than a technical detail. It exposes a fundamental tension within the European project: the Union must be capable of defending the values that justify its existence, but it must do so through the legal powers conferred upon it by the treaties. If a government systematically weakens judicial independence, disregards the principles of democratic accountability or refuses to comply with its European obligations, the question is not simply how the Union should respond politically, but what it is legally entitled to do.

The answer under the current treaty framework is relatively clear in one respect: there is no express procedure for expelling a member state. The more difficult question is whether the existing mechanisms, the general principles of international treaty law or a possible reform of the treaties could provide a lawful response to a situation in which the Union’s constitutional foundations are seriously threatened.

1. Membership as a commitment to common values

Article 2 TEU identifies the values on which the Union is founded, including respect for human dignity, freedom, democracy, equality, the rule of law and respect for human rights, including the rights of persons belonging to minorities. The same provision describes these values as common to the member states in a society characterised by pluralism, non-discrimination, tolerance, justice, solidarity and equality between women and men.

These commitments are closely connected to Article 49 TEU, which governs accession to the Union. A European state seeking membership must respect the values referred to in Article 2 and be committed to promoting them. The Copenhagen criteria, developed by the European Council in 1993, further specify the political and economic conditions associated with accession, including stable institutions guaranteeing democracy, the rule of law, human rights and respect for minorities.

The legal significance of these provisions becomes particularly apparent when a state’s conduct changes after accession. The Union’s founding treaties do not treat membership as an unconditional entitlement detached from the values that originally justified admission. Nevertheless, the fact that a state is required to respect those values does not automatically mean that the Union can terminate its membership when it fails to do so.

This distinction is essential. A legal obligation and a legal power to impose a particular sanction are not the same thing. Article 2 establishes the Union’s foundational values, while other provisions determine how those values can be protected and what consequences may follow from their violation. The absence of an express expulsion clause means that the Union cannot simply assume that a power to remove a member state follows directly from the obligation to respect the values of Article 2.

The principle of conferral, laid down in Article 5 TEU, reinforces this conclusion. The Union may act only within the competences conferred upon it by the member states in the treaties. Although the Union possesses legal personality and operates within an autonomous legal order, its institutions cannot create new powers merely because a particular political situation makes them desirable. Any proposal to expel a member state must therefore confront the limits imposed by the treaties themselves.

2. Article 7 TEU: defending the Union without expelling a member

The principal treaty mechanism for addressing serious threats to the Union’s fundamental values is Article 7 TEU. Its structure distinguishes between the preventive identification of a risk and the determination that a serious and persistent breach has occurred.

Under Article 7(1), a reasoned proposal from one third of the member states, the European Parliament or the European Commission may lead the Council to determine that there is a clear risk of a serious breach of the values referred to in Article 2. The Council acts by a majority of four fifths of its members, after obtaining the consent of the European Parliament, and may address recommendations to the state concerned.

Article 7(2) establishes a more demanding procedure. On a proposal from one third of the member states or the Commission, and with the consent of the European Parliament, the European Council may determine unanimously that a serious and persistent breach of the values referred to in Article 2 exists. The member state concerned does not participate in that vote. Under Article 7(3), following such a determination, the Council may decide by qualified majority to suspend certain rights deriving from the application of the treaties, including the voting rights of the government’s representative in the Council.

Suspension is not the same as expulsion. The state remains a member of the Union and continues to be bound by the obligations arising from the treaties. Indeed, Article 7(3) expressly provides that the obligations of the state concerned remain binding upon it. The Council must also take account of the possible consequences of the suspension for the rights and obligations of natural and legal persons.

Article 7(4) allows the Council to vary or revoke the measures imposed when the circumstances that led to them change. The mechanism is therefore designed to respond to a breach while preserving the legal relationship between the Union and the state concerned.

Its limitations are nevertheless significant. The unanimity requirement under Article 7(2) makes a formal determination of a serious and persistent breach politically difficult, particularly where governments may be reluctant to support measures against another member state. The procedure also does not offer a legal route from the suspension of certain membership rights to the involuntary termination of membership.

Article 7 thus illustrates the distinction between defending the Union’s constitutional values and removing a state from the Union. The treaties expressly authorise the former through a defined procedure, but they do not establish the latter as a sanction. This is an important reason why proposals for an expulsion mechanism continue to attract academic and political attention.

3. Article 50 TEU: a right to leave, but no equivalent right to expel

The Lisbon Treaty, which entered into force in 2009, introduced an explicit withdrawal procedure through Article 50 TEU. The provision allows any member state to decide to withdraw from the Union in accordance with its own constitutional requirements. The state must notify the European Council of its intention, after which the Union negotiates and concludes a withdrawal agreement in accordance with the procedure laid down in the article.

If no withdrawal agreement enters into force, the treaties cease to apply to the state concerned two years after notification, unless the European Council, in agreement with that state, unanimously decides to extend the period. The provision therefore establishes a route out of the Union without requiring the remaining member states to consent to the withdrawing state’s initial decision.

The United Kingdom’s withdrawal demonstrated that Article 50 is not merely theoretical. Following the 2016 referendum, the United Kingdom notified its intention to withdraw in March 2017, and its membership ended on 31 January 2020. The process also exposed the political and legal complexity of disentangling a state from a legal order that had shaped domestic legislation, economic relations and the rights of individuals for decades.

The Court of Justice clarified an important aspect of the procedure in Wightman and Others v Secretary of State for Exiting the European Union (Case C-621/18). In its judgment of 10 December 2018, the Court held that a member state could unilaterally revoke its notification of an intention to withdraw, provided that the revocation was decided in accordance with its constitutional requirements, communicated in writing to the European Council and unequivocal and unconditional. The judgment emphasised that Article 50 provides for a voluntary withdrawal process rather than an irreversible consequence of notification.

The contrast with expulsion is striking. The treaties recognise that a state may choose to leave, but they do not establish an equivalent procedure through which the Union may compel it to do so. Nor does Article 50 provide a mechanism for converting a breach of Article 2 into a forced withdrawal. A state’s persistent disregard for democratic principles or judicial independence cannot, by itself, be treated as a notification of withdrawal under Article 50.

This asymmetry reflects the legal architecture of the Union. The treaties expressly regulate voluntary withdrawal and establish sanctions for certain breaches of fundamental values, but they stop short of authorising the involuntary termination of membership. Whether that omission should be corrected is a separate question from whether such a power already exists under current law.

4. Could general international law provide an alternative?

The absence of an express expulsion clause in the EU treaties does not entirely end the debate. The Union was established through international treaties, and questions concerning the suspension or termination of treaty obligations may also arise under general international law. One provision frequently discussed in this context is Article 60 of the Vienna Convention on the Law of Treaties, which addresses the termination or suspension of a treaty as a consequence of its breach.

Under Article 60, a material breach of a bilateral treaty may entitle the other party to invoke the breach as a ground for terminating or suspending the treaty. In multilateral treaties, the rules are more complex. The other parties may, by unanimous agreement, suspend the operation of the treaty in whole or in part or terminate it in the relations between themselves and the defaulting state, or between all the parties, subject to the conditions laid down in the provision.

Some scholars have argued that these rules could be relevant to the expulsion of a state from an international organisation, particularly where the state has seriously violated obligations that are essential to the organisation’s purpose. The European Parliamentary Research Service examined this question in its 2023 briefing, Suspension and expulsion of states from international organisations: Analysis of the Vienna Convention on the Law of Treaties and of the practice at the United Nations and the Council of Europe. The briefing discusses the possible relevance of Article 60 to the suspension or expulsion of a recalcitrant member of an international organisation, while placing the argument within the broader law of treaties and the practice of other organisations.

However, applying this reasoning to the European Union would raise substantial difficulties. The EU is not simply a conventional international organisation whose membership can be analysed without regard to its distinctive legal order. Its treaties establish institutions with defined powers, a system of judicial protection and a body of law that confers rights on individuals as well as obligations on states. Any attempt to terminate a member state’s participation through general international law would have to account for this particular constitutional structure.

There is also a question of legal interpretation. Article 60 concerns the consequences of a material breach of a treaty, but it does not expressly establish a general power to expel members from every international organisation. Whether and how its provisions could be used to terminate a state’s participation in an organisation depends on the applicable legal framework and the circumstances of the breach. The fact that some scholars consider this route arguable does not establish that it is an accepted or available procedure for expelling a member state from the EU.

Moreover, the principle of pacta sunt servanda, reflected in Article 26 of the Vienna Convention, requires treaties in force to be performed in good faith. It would be difficult to reconcile the defence of the Union’s legal order with an approach that bypassed the institutional safeguards and procedures established by its own treaties without a sufficiently clear legal basis.

International law may therefore inform the debate, but it cannot simply be treated as an alternative expulsion clause that the EU treaties happen to omit. Any reliance on it would involve serious legal questions about the relationship between general treaty law and the specific constitutional framework of the Union.

5. Could the member states create a new Union without the offending state?

A different possibility has been discussed in academic literature: rather than expelling a state from the existing Union, the remaining member states could seek to establish a new legal entity among themselves, potentially preserving or deepening integration without the state concerned. This approach is sometimes described as the creation of a new Union or an “EU 2.0”.

Such a scenario would not amount to expulsion under the current treaties. It would instead involve a fundamental reorganisation of the legal relationships between the participating states. Its advocates may see it as a way to avoid the political deadlock that can arise under Article 7, particularly where the unanimity requirement prevents a determination under Article 7(2).

Nevertheless, the legal and practical obstacles would be formidable. The participating states would have to address the relationship between the existing treaties and any new agreement, the continuity of EU institutions and legislation, the division of assets and liabilities, and the status of rights currently enjoyed by individuals and businesses under EU law. They would also need to consider how such a change would affect the internal market, the EU budget and the Union’s international commitments.

The position of citizens would be particularly sensitive. EU citizenship is conferred on nationals of member states under Article 20 of the Treaty on the Functioning of the European Union. If a state ceased to participate in the existing Union, the consequences for its nationals’ EU citizenship and the associated rights would raise difficult legal questions. These could not responsibly be treated as an incidental consequence of an institutional reorganisation.

Nor would the creation of a new Union automatically resolve the problem of legality. A new treaty would need a defensible legal basis under international law and would have to address the rights and obligations arising under the existing legal order. The political feasibility of persuading the remaining states to undertake such a complex transformation would be uncertain.

The proposal is therefore best understood as a possible political and legal response discussed in scholarship, rather than an established mechanism available to the Union’s institutions. It highlights the potential consequences of the absence of an expulsion clause, but it does not provide a straightforward substitute for one.

6. Reforming the treaties: a clearer legal solution?

If the absence of an expulsion mechanism is considered a weakness in the Union’s constitutional framework, the most transparent solution would be to address the issue through treaty reform. Article 48 TEU establishes the procedures for revising the treaties, including the ordinary revision procedure, under which amendments are agreed by common accord of the member states and enter into force after ratification by all of them in accordance with their respective constitutional requirements.

A treaty amendment could, in principle, establish a specific procedure for the involuntary termination of membership. Such a provision would need to define the circumstances in which it could be invoked, the institutions authorised to initiate the procedure, the voting requirements, the rights of the state concerned to be heard, and the role of judicial review. It would also have to clarify the consequences for the state’s continuing obligations, its citizens and businesses, and the legal certainty of individuals who have relied on EU law.

The threshold for using such a mechanism would be central to its legitimacy. An expulsion procedure triggered by ordinary political disagreement could undermine the equality of member states and expose the Union to accusations that its institutions were using membership as a political weapon. Conversely, a procedure limited to exceptionally serious and persistent violations of the Union’s fundamental values would need to be sufficiently precise to prevent arbitrary application.

Any new mechanism would also have to be considered alongside Article 7 rather than simply duplicating it. The existing provision allows the Union to respond to serious breaches while preserving membership and the state’s underlying treaty obligations. An expulsion clause would represent a qualitatively different sanction, with far-reaching consequences for the legal and political relationship between the Union and the state concerned.

For these reasons, treaty reform would require more than adding a sentence authorising expulsion. It would involve a careful assessment of the relationship between the Union’s foundational values, the principle of conferral, the equality of member states, the rights of individuals and the stability of the European legal order.

Conclusion

Can the European Union expel a member state? Under the current treaties, the answer is that no express procedure for involuntary expulsion exists. Article 7 TEU provides a mechanism for addressing serious breaches of the Union’s fundamental values, including the suspension of certain membership rights, while Article 50 TEU regulates voluntary withdrawal. Neither provision authorises the compulsory termination of membership as a sanction for violating Article 2.

General international law, particularly Article 60 of the Vienna Convention on the Law of Treaties, has been discussed as a possible source of arguments concerning the suspension or termination of participation in an international organisation. However, its application to the EU remains legally contested and cannot be presented as an established route to expulsion. The alternative idea of creating a new Union without a particular member state would raise similarly substantial questions of legality, institutional continuity and individual rights.

The debate ultimately reveals a tension at the heart of European integration. The Union is founded on values that its members are obliged to respect, but the defence of those values must itself remain subject to the rule of law. A response to democratic backsliding cannot be considered legitimate simply because it pursues a legitimate objective; it must also rest on a lawful procedure and respect the constitutional structure through which the Union exercises its powers.

Whether the treaties should be amended to provide for expulsion is therefore a question for political and constitutional debate. What is clear under the current legal framework is that the Union cannot treat an expulsion power as though it were already written into the treaties. The challenge is to ensure that the Union can defend its constitutional foundations without undermining the legal order that gives those foundations practical meaning.