285The European Union’s Accession to the European Convention on Human Rights: The Procedural Dimension and the Limits of Joint Responsibility[*]

Vassilis P. Tzevelekos, Reader in Law, University of Liverpool, School of Law and Social Justice; Member of the UN Human Rights Council Advisory Committee and the Working Group on Communications; Member of the European Committee of the Council of Europe for the Prevention of Torture; Co-Editor-in-Chief, European Convention on Human Rights Law Review

1. Shifting the Focus to Procedure in the Accession Debate

It is a privilege for me to open this issue of Lex&Forum, which brings together papers presented at the workshop entitled The EU Accession to the ECHR: Procedural Hurdles and Prospects before the ECtHR. The workshop took place on 15 and 16 May 2025 at the Faculty of Law of the Aristotle University of Thessaloniki and was organised as a joint initiative of Lex&Forum and the European Convention on Human Rights Law Review. It brought together academics working at the intersection of European Union (EU) law, public international law and human rights law, alongside experts and practitioners with rich institutional experience within the Council of Europe. This combination of academic analysis and practical expertise was deliberate and reflected the ambition of the workshop, which also informs the orientation of this issue.

The accession of the EU to the European Convention on Human Rights (ECHR) is not a new topic. On the contrary, it has long been discussed as a central 286project in European public law. Its history[1] is marked by early political aspirations, prolonged negotiations, periods of institutional hesitation and, most notably, moments of rupture. The failure of the 2013 draft accession agreement[2] following the opinion of the Court of Justice of the European Union (CJEU) in Opinion 2/13[3] represented a significant setback, not only legally but also politically and symbolically. Yet it did not bring the accession process to an end. The negotiations that followed, culminating in the revised draft accession agreement of 2023[4], signalled a renewed political commitment on the part of the EU, the Council of Europe, and their member states to bring this long process to fruition.

This momentum has been accompanied by a growing body of academic literature[5]. Much of this scholarship is focusing, understandably, on the structural dimensions of accession, including the institutional design of the revised draft accession agreement, its compatibility with EU law, the preservation of the autonomy of the EU legal order and the systemic relationship between the CJEU and the European Court of Human Rights (ECtHR). These questions are fundamental and continue to warrant careful scrutiny. At the same time, the sustained concentration of scholarly attention on these questions has left comparatively little space for examining other dimensions that may prove equally consequential once accession becomes operational.

The point of departure for the workshop, and for the present issue, was precisely this observation. Relatively little attention has been paid to questions of procedure and to how accession will function in practice once cases begin to reach the ECtHR. Procedure –which lies at the heart of the focus of Lex&Forum– is often treated as secondary or technical. Yet it is at the procedural level that legal abstraction gives way to concrete operation. In the context of the EU’s accession to the ECHR, it is through procedural rules and practices that the EU’s 287distinctive constitutional structure –characterised by shared competences, executive federalism and mutual trust– will be translated into the framework of international adjudication. It is also at this level that applicants will encounter the ECHR system in practical terms.

The workshop was therefore designed to redirect attention to the procedural implications of accession. To that end, this issue opens the discussion by publishing papers that address selected procedural hurdles and prospects relating to litigation before the ECtHR and to the supervision of the execution (i.e., the implementation) of judgments after accession. Alongside contributions offering broader institutional perspectives from within the Council of Europe and from the perspective of EU constitutional law, the volume includes analyses of specific procedural mechanisms and questions, ranging from the co-respondent mechanism[6] to evidence and the burden of proof, friendly settlements and unilateral declarations, and the execution of ECtHR judgments by the Committee of Ministers. These are not peripheral questions. They are the means through which accession will acquire concrete meaning and will produce practical effects. By bringing these perspectives together, the issue seeks to contribute to the existing literature in a distinct way: it approaches accession as a project that raises procedural law questions. The accession’s success or failure will depend on how effectively the ECHR system can accommodate a non-state actor without undermining its judicial coherence or its applicant-centred orientation. This, in turn, is also a question of legal procedure.

The contributions that follow pursue this reflection from different angles, but with a shared concern: what accession will look like in practice once the EU appears before the ECtHR subject to procedural rules governing its status as respondent, evidence or execution. This concern unites the workshop, but also this issue, and the analysis developed in the remainder of this introduction. While not all contributions focus directly on legal procedure in a narrow sense, they converge on a common question: how responsibility for human rights compliance is to be organised, mediated and ultimately rendered justiciable. This issue demonstrates that legal procedure plays a crucial role in this respect and, as the third part of this introductory note argues, that its significance extends well beyond the practicalities and formalities of procedural rules as such, reaching into the very core of the accession arrangement, including questions of EU autonomy and the joint responsibility[7] of the EU and its member states. Before turning to this point, a few words are necessary on the structure of the issue and the questions addressed by each contribution.

2882. Themes and Approaches across the Contributions

The issue opens with an overview contribution by Christos Giakoumopoulos, former Director General of Human Rights and Rule of Law of the Council of Europe and one of the architects of the accession project from the perspective of that organisation. Drawing on extensive institutional experience, this contribution provides a concise historical account of the accession saga, framed around the claim that the accession has now reached a decisive moment. The note is not intended as a doctrinal intervention, but as a contextual and forward-looking framing of the accession debate from within the Council of Europe system. It situates accession as a long-standing political priority. Normatively, the contribution advances a strong case in favour of the EU acceding the ECHR. Accession is presented as democratically necessary, given the extensive regulatory powers exercised by the EU; legally mandatory under Article 6(2) of the Treaty on European Union[8]; and systemically desirable from a human rights perspective, insofar as it would allow individuals to challenge conduct attributable to the EU before the ECtHR. The author underscores that the Charter of Fundamental Rights of the EU, while significant, cannot replace the collective mechanism established by the ECHR. The contribution concludes with a warning: a further failed accession attempt would risk widening the gap between the EU legal order and the ECHR system, potentially prompting the ECtHR to reconsider the Bosphorus doctrine[9].

From this broader framing, the issue moves to contributions that engage more directly with the procedural “architecture” of accession. Lize Glas examines the role of friendly settlements and unilateral declarations in proceedings before the ECtHR once the EU has acceded to the ECHR. Her analysis is explicitly forward-looking and focuses on how these mechanisms, which play an increasingly prominent role in the ECtHR’s case management, might operate in cases involving EU law. The article distinguishes three scenarios. First, where the EU appears as the sole respondent, friendly settlements and unilateral declarations would, in principle, be available on the same footing as for other ECHR parties, in line with the objective of preserving the existing ECHR mechanism. At the same time, the author cautions that early cases against the EU are likely to raise novel and constitutionally sensitive questions, making routine reliance on these mechanisms difficult to reconcile with the ECtHR’s role in developing ECHR standards. Second, in cases involving the co-respondent mechanism, the analysis becomes more structurally critical. Because responsibility under the 289co-respondent mechanism is formally joint and remains unallocated, the article argues that practical difficulties arise even when cases are resolved without a judgment on the merits. In particular, uncertainty as to which actor must take remedial action risks undermining the effective use of friendly settlements and unilateral declarations in cases involving both the EU and its member states. After rejecting the ECtHR, the Committee of Ministers, and inter-party agreements as appropriate fora for resolving this question, the author proposes that the allocation of responsibility should be determined internally under EU law by the CJEU. Friendly settlements or unilateral declarations could then be used to give practical effect to that internal determination, while preserving the autonomy of the EU legal order. A third scenario concerns the prior involvement procedure, where such mechanisms might facilitate resolution after the CJEU has ruled on compatibility with fundamental rights, albeit at the cost of reduced external scrutiny.

These structural tensions are taken further in Vassilis Pergantis’ contribution, which offers a systematic and critical examination of the co-respondent mechanism as redesigned in the revised draft accession agreement. The analysis focuses on the implications of the mechanism for the proper administration of justice before the ECtHR. While the accession agreement formally relies on a classical model of attribution, distinguishing between EU institutions and state organs, the article demonstrates that this binary logic is ill-suited to the constitutional reality of the EU. Executive federalism, overlapping competences and situations of constrained national discretion require a mechanism that blends attribution of conduct with attribution of responsibility. Building on this insight, the article develops a critique of the co-respondent mechanism as redesigned in the 2023 draft accession agreement. It argues that the revised structure introduces an element of self-judgment into a system otherwise premised on judicial control. By allowing the EU to determine who is the (co-)respondent party to the proceedings, the mechanism risks undermining the judicial function of the ECtHR, distorting equality of arms and jeopardising effective remedies for applicants. The contribution also raises concerns about bad faith use of the co-respondent mechanism and the absence of robust safeguards against abuse. It explores whether the ECtHR might nonetheless retain some control by reviewing the outer limits of the EU’s reasoned assessment, for example in cases of manifest lack of reasoning, undue delay, or abuse of rights, while acknowledging the uncertainty surrounding such corrective strategies.

Christine Bicknell approaches post-accession procedural hurdles from the perspective of evidentiary dynamics, using burden of proof as a lens through which to assess accession. The article identifies the structural constraints that shape post-accession litigation, including the autonomy of EU law, regimes of mutual trust and mutual recognition, and the redesigned co-respondent mechanism. 290Against this background, it examines how questions of burden of proof are addressed in practice, showing how evidentiary reasoning operates within these constraints and brings to the fore underlying questions of causation and responsibility, even where formal attribution remains limited. The core analysis distinguishes between three scenarios: complaints concerning the conduct of EU institutions; complaints against member states implementing EU law, with or without discretion; and complaints arising from mandatory co-operation between member states under mutual trust regimes, such as asylum transfers and European Arrest Warrants. In cases involving direct action by EU bodies, the article highlights the difficulties applicants may face in establishing factual proof and draws analogies with disappearance cases where evidentiary burdens may shift once a prima facie case is established. In the other types of cases concerning member state action implementing EU law, the burden of proof may expose tensions between the EU and its member states, particularly where discretion, causation and responsibility are contested. The article concludes that, although joint responsibility formally avoids allocation, evidentiary reasoning may reveal causal responsibility in practice.

The execution stage is addressed by Zoë Bryanston-Cross, who brings to the analysis extensive practical experience from within the Committee of Ministers. Drawing on the supervisory acquis, the contribution outlines the core principles governing execution of judgments of the ECtHR, including feasibility, timeliness, adequacy, good faith and respect for the conclusions and spirit of the ECtHR’s judgment. Central to this framework is the principle of choice of means, under which the respondent determines how to execute a judgment. The article emphasises that most cases are supervised without recourse to voting and that many cases require little more than payment of just satisfaction. This underlines the limited practical impact of the institutional adjustments introduced by the accession agreement and the continuity of the supervision process post-accession. Where the EU and one or more member states are held jointly responsible, the ECtHR’s judgment fixes joint liability, which the Committee of Ministers cannot revisit. Supervision is not concerned with allocating responsibility, but with ensuring effective remedial measures. Decisions as to who does what in practice are left to the co-respondents themselves, within a framework focused on results rather than attribution or allocation of execution tasks and responsibilities.

The issue concludes with a contribution by Joseph Ktenidis, offering analytically framed reflections from the perspective of EU constitutional law. Τhe article develops three targeted lines of analysis: the position of applicants post-accession; the internal functioning of the EU legal order; and the status of the EU as a contracting party to the ECHR. From this perspective, accession is presented as enhancing judicial protection by enabling direct applications against 291the EU and addressing accountability gaps. At the same time, the contribution highlights unresolved questions concerning internal implementation, including the need for secondary legislation, institutional competence and judicial review within the EU. The article also stresses the structural tension between the autonomy of EU law and the dependence of the Union on its member states as masters of the Treaties. Treating the EU as a unitary sovereign actor within the ECHR system, the author argues, risks obscuring this constitutional reality and oversimplifying the challenges of accession.

3. Beyond Procedure: Joint Responsibility and its Artificiality under Procedural Stress

Taken together, the contributions reveal that procedural operation is not merely an instrument for managing cases post-accession, but the terrain on which the accession’s deepest structural questions arise. Across adjudication, evidentiary assessment, settlement and execution, the responsibility of the EU and its member states under the co-respondent mechanism is framed as formally joint, yet is in practice capable of differentiation. This tension provides the foundation for a closer examination of joint responsibility and its limits within the framework of the EU’s accession to the ECHR.

Joint responsibility occupies a central place in the architecture of the revised draft accession agreement. It is presented as a solution capable of reconciling, on the one hand, external scrutiny of the EU legal order by the ECHR system and, on the other, the autonomy and distinctive constitutional features of the EU, characterised by shared competences and overlapping forms of action. At the level of institutional design, joint responsibility appears to offer an elegant compromise. At the level of procedure, however, its limits become increasingly apparent.

What emerges from most of the analyses developed in this volume is that joint responsibility operates largely as a formal construct. It enables proceedings to move forward without requiring the ECtHR to engage in sensitive questions concerning the internal allocation of competences within the EU legal order or the distribution of responsibility between the EU and its member states. In that sense, it fulfils an important stabilising function. At the same time, the contributions repeatedly demonstrate that joint responsibility does not eliminate, but rather displaces, the underlying questions of causation, responsibility and remedial obligation.

This displacement becomes visible across different procedural stages. In adjudication, the co-respondent mechanism allows responsibility to be framed jointly, while leaving unresolved the question of who, in practice, caused the alleged violation and the extent to which they bear responsibility for it. In evidentiary reasoning, questions of causation and responsibility re-emerge through the operation of the burden of proof. In settlement procedures, uncertainty 292as to “internal” responsibility and its allocation complicates the effective use of friendly settlements and unilateral declarations. At the execution stage, while the Committee of Ministers does not allocate responsibility and leaves the practical distribution of remedial action to the co-respondents themselves, the problem of internal allocation may nonetheless persist.

This is all the more striking because joint responsibility is traditionally conceived as appropriate where it is genuinely impossible to allocate responsibility between actors. In the context of the EU’s accession to the ECHR, however, joint responsibility serves a different function. It is employed not because the ECtHR is incapable of allocating responsibility between the EU and its member states, but because it must be prevented from doing so. The rationale for this restraint lies in the need to avoid interference with the allocation of competences within the EU legal order and, more broadly, with the constitutional relationship between the EU and its member states, so as to preserve the autonomy of the EU legal order as understood and defined by the CJEU.

On the one hand, joint responsibility is a necessary condition for the EU, and its Court of Justice, to accept subjection to the authority of the ECtHR. From this perspective, it may be understood as a “reasonable adjustment”[10] that enables a sui generis polity, such as the EU, to fit within the ECHR model. On the other hand, within this framework joint responsibility acquires an artificial quality. Although the EU and its member states are distinct legal persons and actors, they appear before the ECtHR under the co-respondent mechanism as if they constitute a single entity. This artificiality is not merely conceptual; it is exposed in practice through the operation of different procedural stages and mechanisms.

Across these contexts, a common pattern can be observed. Joint responsibility facilitates institutional accommodation within the ECHR system, but it does so by abstracting away from the differentiated nature of action within the EU. The EU and its member states do not act as a single actor, nor do they operate through a unified chain of command. Their relationship is structured by internal rules on competence, discretion and mutual trust, which remain legally and practically salient even when responsibility is framed jointly at the international level. Procedure brings this tension to the surface precisely because it is concerned not only with how responsibility is formally labelled, but with access, proof, remedies and compliance.

Seen in this light, joint responsibility cannot be regarded as a neutral or self-sufficient solution. While it may be understood as a legal construction that 293enables the ECHR system to accommodate a non-state actor without intruding into its internal allocation of powers and institutional dynamics, at the same time, it leaves unresolved, and in some cases exacerbates, questions that reappear elsewhere in the procedural life of a case.

The procedural focus of this special issue, thus, serves a broader purpose that extends beyond procedure as such and touches upon the systemic features and core design of the accession arrangement. By examining how accession is likely to function in practice, the contributions expose the limits of solutions that may appear satisfactory at the level of institutional design but prove fragile when translated into procedural operation. In doing so, they collectively suggest that the success of accession will depend not only on the formal arrangements governing the framing of responsibility, but also on the willingness of all actors involved, including the institutions of the Council of Europe, to confront the tensions that joint responsibility seeks to smooth over.

It is in this sense that the procedural lens adopted in this volume is not merely complementary to existing analyses assessing the design of the draft accession agreement and its compatibility with EU law, but also corrective. It shifts attention from how responsibility is formally framed to how it will be experienced and implemented in practice. Whether joint responsibility can sustain that burden over time remains an open question. What this special issue aims to show is that answering it requires close and sustained attention to legal procedure.

[*] The views expressed in this contribution are solely those of the author and do not reflect the views of the institutions with which he is affiliated.

[1] Parliamentary Assembly of the Council of Europe, Committee on Legal Affairs and Human Rights, “Legal aspects of the accession of the European Union to the European Convention on Human Rights” (Rapporteur: Titus Corlățean, 7 March 2025) Doc. 16126.

[2] Council of Europe, “Fifth Negotiation Meeting Between the CDDH Ad Hoc Negotiation Group and the European Commission on the Accession of the European Union to the European Convention on Human Rights” (10 June 2013) 47+1(2013)008rev2.

[3] CJEU, Opinion 2/13, Accession of the European Union to the European Convention for the Protection of Human Rights and Fundamental Freedoms [2014], ECLI:EU:C:2014:2454.

[4] Council of Europe, “Final Consolidated Version of the Draft Accession Instruments” (17 March 2023) 46+1(2023)36 (draft accession agreement of 2023).

[5] See, for instance, S.Ø. Johansen/G. UIfstein/A. Follesdal/R. A. Wessel (eds.), The Revised Draft Agreement on the Accession of the EU to the ECHR (2024), 9(2) European Papers. 641; K. Dzehtsiarou/V. P. Tzevelekos (eds.), The New Agreement on the EU Accession to the ECHR: Can It Succeed? (2025), 6(1) ECHR Law Review. 1.

[6] Draft accession agreement of 2023 (n 3), Article 3.

[7] Ibid.; Article 3(8) and Explanatory Report of the draft accession agreement of 2023, §§ 29 and 71.

[8] Consolidated Version of the Treaty on European Union [2012], OJ C326/13 (TEU), Article 6(2).

[9] ECtHR, Bosphorus Hava Yolları Turizm ve Ticaret Anonim Şirketi v. Ireland [GC], 45036/98, 30 June 2005, §§ 152-158.

[10] V. P. Tzevelekos, in The system of the European Convention on Human Rights: Responding to New Trends and Challenges, Proceedings of the Conference, Strasbourg, 24 June 2025 (Council of Europe, 2025), p. 95.