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  • Writer's pictureJosh Thompson

EU law, the ECJ, supranational constitutionalism and the question of democratic qualification.

Updated: May 31, 2022

What is the democratic basis for the constitutional jurisprudence of the ECJ? Over the decades the ECJ has expanded the scope of its competencies through the use of legal tools, logic and methods of interpretation in case law. With the ECJ adopting increasingly widening constitutional competencies this raises the question as to how the supranational constitutional mandate of the ECJ is to be framed in relation to the constitutionalism of the Member States and their respective constitutional courts? Why exactly do national courts accept the constitutional jurisprudence of the ECJ given the apparent lack of obvious, or express direct democratic qualification? Central to both these questions is the concept of legitimacy. By moving constitutionalism beyond the remit of a traditional national constitutional theory and the boundaries of a national political system the democratic qualifications attached to the supranational constitutionalism of both Treaties and the jurisprudence of the ECJ becomes unclear. From where can we derive the democratic credentials of the ECJ’s supranational constitutional jurisprudence? It is my intention to briefly tackle the question of legitimacy by first presenting a brief account of the concept of constitutional courts and constitutional jurisprudence before moving to consider the potential source of democratic, or meta-democratic qualification of the supranational constitutionalism evident in EU law.

Ordinary courts and constitutional courts

A useful starting point for this discussion is to first consider what is a constitutional court and what is constitutional jurisprudence? This is an important question to address as a preliminary point as by outlining what each term means we can in turn better identify the ECJ and in turn better address questions of legitimacy and democratic qualification.

A constitutional court is a court established by law specifically for the purposes of commenting on constitutional matters.(1) The function of a constitutional court is to act as guardian of the constitution, and to guarantee the supremacy of the constitution thus reinforcing the rule of law within the state. The tools available to constitutional courts varies widely from legal system to legal system. Equally so does the exact placement of the constitutional court within the judicial hierarchy however the commonality is always that the constitutional status of the entity in question is expressly provided for by law which differentiates these constitutional courts from ordinary courts that do not possess the competencies to review the constitutionality of legislation, acts of the Parliament or any additional areas specified as being a constitutional competency.

Where a court is conferred the express competency of constitutionalism by law the constitutional jurisdiction of that court is largely beyond questions – it is a factual reality specified under by law but it is not the only one. A court may not be expressly a constitutional court, defined separately to ordinary courts, but still nonetheless possess constitutional jurisdiction. Often in the course of carrying out its functions as the judiciary, a court of final instance may be forced to comment on the constitutionality of a specific act, or decision. This ad hoc constitutional jurisdiction arises through the use of tools and methods by the court in the course of fulfilling its functions.

Three notable examples of such a phenomenon relevant to the topic of EU law are the Supreme Courts of the UK and Ireland and the Danish Højesteret. All three, by virtue of their status as courts of final instance have all developed a form of ad hoc constitutional jurisprudence and thus can be considered to possess constitutional jurisprudence much like a separate constitutional court. While the constitutional jurisprudence of each legal tradition can vary, they nonetheless possess a number of common characteristics; they each view themselves as being the guardians of the constitution.(2)

Constitutional jurisprudence and constitutional language

All courts that possess constitutional jurisprudence employ a form of legality which dictates their supremacy within the national judicial hierarchies on matters pertaining to constitutionalism. As noted, this jurisprudence may arise via explicitly legislative or constitutional provisions or it may arise via the employment of tools and methods by the relevant court in case law. Constitutional language can be understood as the use of logic, tools, principles and methods of constitutional interpretation that resemble those employed by a constitutional court.(3) Monica Claes has identified the power of judicial review as a key area of law wherein constitutional language is employed and a forum wherein constitutional jurisprudence is typically expanded.(4)

An example of such a phenomenon can be found in the UK’s long-standing debate regarding the foundation of judicial review and the ultra vires principle. As part of the immense scholarship resulting from this debate, Paul Craig presented an insightful account of the historical development of the power of review and its gradual expansion.(5) Through the research presented by Craig it is possible to clearly map the expansion of the judiciaries constitutional jurisprudence beginning with its humble genesis in Bagg’s Case, where the King’s Bench confirmed that the judiciaries common law power of mandamus permits not only the correcting of judicial errors, but of other extra judicial errors.(6) While relatively simple in its formulation the impact of the decision in Bagg’s Case is significant as it indicated that the judiciary does possess an inherent constitutional jurisdiction and that this jurisdiction is capable of expansion via the use of the judiciary's own logic and dictum.

When we turn to view the judicial activity of the ECJ a similar pattern of evolution through constitutional language can be observed. Van Gend en Loos, Costa v ENEl, Simmenthal and Francovich are all notable examples of instances wherein the court invoked and expanded the scope of its constitutional jurisprudence through the use of various tools such as direct effect, supremacy, state liability, and so on. The result of the ECJ’s constitutional language has been the transformation of the Treaties from being an ordinary species of international treaty into fully fledged framework of documents better resembling a constitution. This change can be traced through a number of notable cases beginning with Opinion 1/76 Laying-up Fund where the court employed the use of constitutional language and referred to the then European Community’s “internal constitution”.(7)

In Les Verts, the court employed the use of constitutional language in relation to the legal status of the European Parliament and its locus standi before the court as a defendant.(8) With reference to the internal constitution of the Community and the rule of law the court expanded the power of review to apply to all Member States and Institutions on the basis that per the rule of law, review must be available. In Opinion 1/91 the court employed a much stronger form of constitutionalism by differentiating the EEA Treaty, as being an ordinary international treaty, and the EEC Treaty which constitutes the constitutional charter of the Community. The court continued and stated that primacy is an essential feature of not only the Treaties, but of Community law itself.(9) What differentiates Opinion 1/91 from Les Verts, Van Gend en Loos or Costa v ENEL is that the form of language employed by the court is far more general and wide reaching. It is less a statement regarding a specific tool or method such as review, direct effect or supremacy but a general statement on the constitutional nature of EU law as a legal system in its entirety.

The various examples of constitutional language in the case law typically arise within the context of judicial review or preliminary reference proceedings. As such, there are few examples of the use of constitutional language outside of the context of review or reference proceedings. As a result of the rule of law crisis in the EU, a large body of case law has emerged wherein the court has issued opinion and judgment on a number of key topics through the use of constitutional language. While a large volume, in fact almost all of them, arose within the context of review or preliminary proceedings there are two cases in particular, C-156/21 Hungary v Parliament and Council and C-157/21 Poland v Parliament and Council, that offer a rare opportunity to observe the use of constitutional language within the context of infringement proceedings. While both cases when viewed together present a rather robust and affirmative defense of the EU legal order, what is of specific interest is how the court arrived at his position.

Of particular note is the court clarified a working definition for the concept of the rule of law as provided for under Article 2 TEU.(10) Thus far, this is the closest we have come to seeing the court define the rule of law as a standalone foundational concept without reference to judicial independence under Article 19 TEU. The basis for the definition was derived from Regulation (EU, Euratom) 2020/2092, which in turn constructed its definition using a framework of sources namely the Treaties, the case law of the ECJ and the Charter of Fundamental Rights of the European Union.(11) What is of specific relevance is that as part of the proceedings Poland and Hungary jointly argued that the definition provided for under the contested regulation should be annulled on the basis that the regulation lacked certainty, clarity, proportionality and that is infringed upon the national identities, or specifically the national constitutionalism, of the Member States.

It is in respoke to the argument raised by the parties that the court upheld the definition cited within the contested regulation through the employment of constitutional language which interpreted the definition, and thus the sources cited by the regulation, through constitutional interpretation. In addition, the court went a step further and specified that not only is the rule of law capable of being defined through the format of a non-exhaustive list of qualities but that the rule of law as a concept contained under Article 2 TEU is capable of possessing substantive content.(12)

The theme of evolution through case law is easily observable throughout the case law of the ECJ noted above. Much like the common law approach found in the UK and Ireland, the ECJ has employed the use of its own logic, principles and interpretation to expand the parameters of its competencies into overtly constitutional territory. The net consequence of the constitutional jurisdiction of the ECJ is that EU law has developed into a constitutionally superior law by virtue of the ECJ adopting methods of interpretation akin to a constitutional court. Claes comments that the constitutionalizing of the EU is directly linked to the constitutional jurisprudence of the ECJ.(13) In light of the above, it is clear that the ECJ is prepared to enter into the forum of constitutionalism however unlike a national constitutional court, the ECJ is not qualified through constitutional convention, or democratic credential deduced through the existence of an elected legislative.

Answering the legitimacy question: An EU Parliamentary model?

Where a court is conferred with express constitutional jurisdiction by virtue of it being a constitutional court established by law there is little issue in identifying the democratic credentials of said courts constitutional jurisprudence. Where the court is not a constitutional court, but it does possess constitutional jurisprudence finding democratic qualifications is somewhat more complicated. While the ECJ is not expressly a constitutional court, it is clear that it does possess a constitutional jurisdiction which in turn has imbued EU law with a constitutional supremacy which sits at the top of the legal hierarchy however the ECJ does not derive direct democratic qualification as it is a supranational court which is established through supernational constitutionalism. This fact raises a number of complex legitimacy questions as to the democratic validity and acceptance of the court's supernational constitutional jurisprudence.

Perhaps before diving into the complex observations above it would be more beneficial to tackle this issue one step at a time. While the ECJ is a supranational court that possess supranational constitutional jurisprudence there are still come comparative observations that can be made between the supranational jurisprudence of the ECJ and the national constitutional jurisprudence of the UK’s judiciary. The constitutional jurisdiction of the UK judiciary is largely qualified through the concept of parliamentary sovereignty. The concept entails a normative understanding of the mechanics of judicial review and specifies that the judiciary is not so much using its powers of review per its own logic but instead it is implying the abstract will of the legislative – Parliament is thus king in the British common law kingdom. While the debate on the exact foundation of judicial review is far from concluded this does appear to be the current position accepted by the UKSC as observed through the recent case of R (Miller) v The Prime Minister.(14)

While contentions, the grounding of judicial review in the bedrock of parliamentary sovereignty results in an important democratic consequence - the judiciary is capable of deriving democratic credentials through the grounding of its constitutional jurisprudence within the remit of the will of an elected legislative. Judges are not elected, but MPs are and thus the court is able to piggyback off the democratic credentials of Parliament in the course of its work. However strenuous this democratic link is it is nonetheless a foundational normative principle within British constitutional theory.(15) Perhaps in the same manner in which the British judiciary derives democratic qualification so to can a fig leaf be found for the ECJ?

Following on from the Parliamentary model discussed above the first place we should begin should be to access the legislative as a potential source of democratic qualification. The European Parliament and Council enjoy joint-legislative functions.(16) When viewing the European Parliament, a level of democratic qualification can be established by virtue of its elected composition.(17) While the formula used to establish the composition of MEP’s has received notable criticism this nonetheless does not detract from the purpose of exploring the potential for the European Parliament to serve as a basis for supranational constitutional legitimacy. Much like the British Parliamentary system is faced with the issues such as the constitutionalisation of political parties(18) and the West Lothian Question(19), one would be remise to outright dismiss the democratic qualifications of the British Parliamentary system as a whole. Turning to the Council we can establish a source of democratic qualification by way of it being comprised of ministers from the Member States who derive their own democratic mandates by virtue of being elected nationally.(20) The democratic credentials of both Institutions is further strengthened through the requirement that they must convene in pubic when debating legislative acts.(21)

In light of the above observations is it possible to derive form manner of democratic, or meta-democratic qualification for the constitutional jurisprudence of the ECJ? At first glance one may be inclined to say yes. Throughout the case law of the ECJ there are a number of examples wherein the court has employed the constitutional language of interpretation and review in relation to directives and regulations. The prior referenced C-1/56 and C-1/157 are appropriate examples this phenomenon. An argument could be made for the democratic, or meta-democratic credentials of the court's constitutional jurisprudence in such instances of proceedings relating to directives and regulations however such an argument does not withstand scrutiny.

While possessing some manner of constitutional character by virtue of their enjoyment of supremacy, secondary legislation does not form the majority of what we can consider the European constitution which is better understand as a framework of documents and sources which enjoy a superior position in the legal hierarchy.(22) This is supported through the simple fact that a large bulk of the courts case law wherein its constitutional jurisprudence was developed is in relation to the Treaties themselves and not exclusively secondary legislation. In addition, adopting a legislative supremacy model within the context of EU law also does not adequately clarify the relationship between the constitutional jurisdiction of the Member States and the supranational constitutional jurisdiction of the ECJ nor does it provide an explanation as to why Member States have come to accept the constitutional jurisdiction of the ECJ at all? It is clear that if we are to find some form of democratic legitimacy for ECJ’s constitutional jurisprudence we must look further.

Sourcing democratic qualification through the Treaties

The Treaties themselves may offer some potential for the sourcing of democratic credentials for the jurisprudence of the ECJ however in order to ascertain this possibility two issues must be clarified; what does the term “European constitution” mean and who are the stakeholders in relation to this constitution, or rather how exactly did this constitution come to be?

The concept of a constitution should be viewed broadly. Just as we have observed prior in regards to the varying forms of constitutional courts that exist across the various legal traditions in Europe, so to does the form and content of their respective constitutions. Ingrid van BIezen offers a vision of a constitution as being a set of fundamental values, whoever incomplete, which outline the procedural rules that organize the use of power and that define the relationship between institutions and citizens.(23) Claes notes that the vast majority of cases wherein the court has employed prolific constitutional language has been in relation to cases which concern the duties and obligations of the Institutions specifically.(24) Following the logic of Van Biezen and Claes it is quite clear that the Treaties are capable of possessing some qualia of constitutionalism as they provide for a set of fundamental values, procedural rules and they outline the relationship between the Institutions and the Member States. While I believe there is a compelling argument in support of the constitutional status of the Treaties what does the ECJ have to say on the matter?

In Les Verts and Opinion 1/91 we have seen the court employ the term “internal constitution” in reference to the Treaties. While the court has since avoided the use of such language too liberally over the decades, the court has not shied away from employing some form of constitutional language when discussing the Treaties. In C-157/21 the court stated once a state joins the EU, it joins the legal structure based upon a shared set of common values upon which the Union is founded as referenced under Article 2 TEU.(25) The court continues and references the rule of law as being developed by the court on the basis of the Treaties.(26) A theme of constitutionality can be detected in the statements of the court. By specifying the centrality, and supremacy, of the rule of law as a concept within the EU legal order, and further clarifying the both the mechanism through which it is defined and the source from which it is derived, the court has enunciated a constitutional interpretation of Article 2 TEU.

From the above it is clear that the Treaties are capable of possessing a constitutional character. Claes observes that the the constitutional character of the Treaties, and the process of constitutionalisation in Europe is linked to the constitutional jurisprudence of the ECJ.(27) A constitution has been identified, and we have established an almost circular pattern of inter-relation between the Treaties, and the jurisprudence of the ECJ but how exactly can this relationship be cited as a source of potential democratic qualification for the ECJ’s constitutional jurisprudence? The key to answering this question is through the concept of Union Membership - the Member States themselves have voluntarily committed to the Treaties and curtailed their sovereignty in certain areas. In C-619/18 the court emphasized the fact that by becoming members of the EU, a joining state freely and voluntarily commits themselves to the common values of the Union as provided for in the Treaties.(28) The court employs a similar form of language in C-791/19 by reiterating its earlier position in C-619/18 and emphasizing that by becoming Member States each joining state has voluntarily committed themselves to the common values expressed under Article 2TEU which themselves are derived from the common societal norms of each of the Member States.(29)

Perhaps by relying upon the circular relationship between the Treaties as a form of ah hoc constitution and the constitutional jurisprudence of the ECJ we can establish some link between the activity of jurisprudence of the court and potential sources of democratic validity. The Treaties represent the common foundational values of the Union, derived from the respective societal and legal cultures of the Member States who in turn have voluntarily submitted themselves to the supremacy of the Treaties and thus the constitutional jurisprudence of the court. While this is certainly a more strenuous form of democratic validity than that present in national legal systems this is nonetheless enough to confirm that while the ECJ may lack direct democratic qualification it does in fact enjoy a degree of meta-democratic qualification derived from the Treaties and the voluntary submission of the Member States by way of membership to the Union.


Clarifying the connection between the constitutional jurisprudence of the ECJ and the Member States, through the proxy of the Treaties, imbues the ECJ with a degree of meta-democratic credentials. This observation does not fully outline the relationship between supranational and national constitutionalism within the context of EU law. As EU law has come to possess constitutional qualia through the constitutional jurisprudence of the ECJ this has logically resulted in judgments, orders and opinions that potentially entail statements of a constitutional substance conflicting with national constitutional theory. In such circumstances of conflict EU law naturally enjoys the privilege of supremacy provided the relevent area of law is within the competency of EU law. Claes comments that there should be a degree of reluctance when relying upon the ECJ as a primary driving force behind the constitutionalizing of the EU.(30)

While we can identify meta-democratic qualifications it is difficult to ignore the reality that this connection is tenuous. By virtue of its subject matter and scope, constitutionalism is not solely a judicial exercise but it is one that is jointly political and judicial. While the ECJ certainly possess the jurisdiction to interpret the Treaties as any national constitutional court would, the source of its democratic qualification requires further enforcement. It is clear that the legitimacy question of the jurisprudence of the ECJ as an example of supranational constitutionalism is not as straightforward as that to be observed in national legal systems.


  1. Monica Claes, The National Court’s Mandate and the European Constitution (Hart Publishing 2006) Ch 13

  2. ibid pg 397

  3. ibid pg 403 – 404

  4. ibid pg 392

  5. Paul Craig, Ultra Vires and the Foundations of Judicial Review, in Judicial Review and the Constitution, edited by Christopher Forsyth ( 1st edn Hart Publishing 2000)

  6. Baggs Case (1615) 11 Co. Rep. 93b, 98a

  7. Opinion 1/76 Laying-up Fund [1977] ECR 741, para 12

  8. C - 294/83 Les Verts [1986] ECR 1339

  9. Opinion 1/91 on the EEA Agreement (no. 1) [1991] ECR I–6079

  10. C-157/21 at para 3

  11. Article 2 Regulation (EU, Euratom) 2020/2092

  12. C-157/21 at para 326

  13. Monica Claes, The National Court’s Mandate and the European Constitution (Hart Publishing 2006) at pg 402

  14. R (Miller) v The Prime Minister (2019) UKSC 41

  15. For the full discussion on this topic see Judicial Review and the Constitution, edited by Christopher Forsyth ( 1st edn Hart Publishing 2000)

  16. Arts 14(1) and 16(1) TEU

  17. Article 14(2) TEU

  18. See Jongcheol Kim, Constitutionalising Political Parties in Britain (1998), PhD Thesis, London School of Economics and Political Sciences, Thomas Daly and Brian Jones, ‘Parties versus democracy: Addressing today’s political party threats to democratic rule’, International Journal of Constitutional Law, Volume 18, Issue 2, July 2020 and Ingrid van Biezen, ‘Constitutionalizing Party Democracy: The Constitutive Codification of Political Parties in Post-war Europe’, British Journal of Political Science (2012)

  19. The West Lothian Question, Oonagh Gay, House of Commons Library SN/PC/2586, 26 June 2006

  20. Article 16 (2) TEU

  21. Art 15(2) TFEU.

  22. Monica Claes, The National Court’s Mandate and the European Constitution (Hart Publishing 2006) pg 404 – 405

  23. Ingrid van Biezen, 'Constitutionalizing Party Democracy: The Constitutive Codification Of Political Parties In Post-War Europe' (2012) 42 British Journal of Political Science pg 190

  24. Monica Claes, The National Court’s Mandate and the European Constitution (Hart Publishing 2006) pg 413

  25. C-157/21 at para 5

  26. ibid para 291

  27. Monica Claes, The National Court’s Mandate and the European Constitution (Hart Publishing 2006) pg 401 - 402

  28. C-619/18Commission v Poland (Independence of the Supreme Court) at para 42

  29. C-791/19 Commission v Republic of Poland at para 50

  30. Monica Claes, The National Court’s Mandate and the European Constitution (Hart Publishing 2006) pg 414 – 415

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