1  The case law of the Court of Justice of the European Union (CJEU or ‘Court’) has had a major de facto impact on European integration and the development of European Union (EU) law (see inter alia Stone Sweet). The CJEU’s case law is referred to as a binding source of law by the Court itself and by Member States and EU institutions. Moreover, it often precedes legislative developments in EU and Member State law, in the sense that developments in the case-law may be expressed in codified form in changes made to the Treaties, or in EU regulations or directives, or may be taken up in national law, as appropriate. The role of the CJEU in the European integration process and its role for EU law has been extensively analysed in academic literature (see bibliography). There is consensus that on the one hand the Court, like any other EU institution has to respect the principle of conferral, or attribution of powers, so its powers are limited to those conferred upon it by the various Treaties or by virtue of those Treaties (Streinz, 2011). Yet the Court’s wide jurisdiction is clearly envisaged in the second sentence of Article 19(1) Treaty on European Union (‘TEU’), being to ‘ensure that in the interpretation and application of the Treaties the law is observed’. The legal status and the effect of CJEU cases have, however, been disputed. The widely accepted view is that judgments are formally binding only inter partes, so there is no English law-style rule of stare decisis. However, the Court frequently cites past judgments to support its analysis and conclusions and only rarely departs from an earlier line of cases-law. All judgments of the CJEU—in whatever type of proceedings—thus make clear what the legal position is in EU law.

2  This entry is organized as follows: first, a short summary of the institutional organization of the CJEU is set out, followed by an analysis of the mandate provided to the CJEU by the Treaties and the different types of cases which can come before the CJEU. Attention then turns to summarizing the most important scholarly literature on the role of the CJEU. Finally, the legal relevance and effects of judgments of the CJEU are discussed.

3  The CJEU is, like the European Parliament (European Parliament: Composition and Election – EU Law), European Council, the Council of the European Union (‘Council), the European Commission (European Commission: Tasks, Functions and Powers), the European Central Bank (ECB), and the Court of Auditors, an institution of the European Union (Art. 13(1) TEU). The CJEU currently comprises two Courts: the Court of Justice itself, and the General Court. While the possibility of establishing specialized courts is still open, as the CJEU ‘includes the Court of Justice, the General Court, and specialised courts’ (Art. 19(1) TEU, see also Art. 257 Treaty on the Functioning of the European Union (‘TFEU’)), the only specialized court set up so far, the EU Staff Tribunal, was established on 2 December 2005 and dissolved on 1 September 2016, when its functions were transferred to the General Court. The Court of Justice consists of one judge from each Member State (Art. 19(2) TEU), which means that there are at present 27 judges.

4  Both the Court of Justice and the General Court work according to the principle of collegiality, so that a single judgment is pronounced, with no dissenting judgments; it has been argued that this affects the quality of judgments (Jacobs, 2000), and it may be thought that the state of EU law is now strong enough to withstand a change in approach—the European Court of Human Rights has no difficulty in functioning authoritatively using majority judgments where necessary. For many years now, the Court sits in Chambers, or, where necessary, as a Grand Chamber (Arts. 16–17 Statute of the Court of Justice of the European Union (‘CJEU Statute’); Arts 27 et seq Rules of Procedure of the Court of Justice, or, less frequently as a Full Court (Art.16 CJEU Statute). The Court of Justice is assisted by eleven Advocates General who present their ‘Opinions’ (or in preliminary reference procedure concerning the Area of Freedom, Security, and Justice, under Arts 107–14 Rules of Procedure of the Court of Justice, ‘Views’) to the Court as to how it should decide cases brought before it. This office was designed after the French image of the ‘commissaire du gouvenement’. In the past, an Advocate General was used in all cases, although nowadays, if the Court considers that the case concerned raises no new point of law, it may, after hearing the Advocate General, determine the case without a submission from the Advocate General (Art. 20 CJEU Statute).

5  The General Court now consists of two judges per Member State, which means that it has 54 judges; it too sits in Chambers, or, where necessary, as a Grand Chamber or as a Full Court, or may be constituted by a single judge (Art. 50 CJEU Statute; Arts 13 et seq Rules of Procedure of the General Court (‘GC Rules of Procedure’)). While the General Court has no Advocates General, its members may be called upon to perform the task of an Advocate General, should the General Court consider that the legal difficulty or the factual complexity of the case so requires (Art 30 GC Rules of Procedure; as to the procedure, see Art. 31).

6  The CJEU’s main function as an institution is first to serve as the ‘third power’ in the political system of the European Union, overseeing the acts of the EU institutions and of the Member States for their compliance with EU law. The CJEU is also a partner in the multi-level judicial system of legal protection in EU law. In this system of centralized and decentralized judges of EU law, it ‘communicates’ via the preliminary reference procedure (Art. 267 TFEU) with national courts (the decentralized judges), securing the uniform interpretation of EU law by providing binding judgments on its interpretation and application. This procedure is the jewel in the crown of the EU legal system.

7  As a supranational institution devoted to the observance of the law, the Court has also adopted a much wider mandate than simply that of ‘policeman’. In an incomplete legal system such as that of particularly the early years of the EU (Lenaerts, 2013, 15, 16; Purnhagen, 2013, 144–45), the Court’s role was described as a constitutionalizing Court (Caruso, 2006, 29), whose law-creating ambitions have been described as a necessary requirement to build an otherwise fragmented supranational legal order (Weiler, 1981, 267; Weiler, 1991, 2403). This wide interpretation reflects the special status of the Court in an institutional system, which does not comprise ‘a conventionally elected legislature or a conventional executive or government produced by party politics which dominates that legislature’ (Shaw, 2001, 120–21). Meanwhile, the institutional structure has changed and the European Parliament has been given a much stronger role to play in the institutional system of the EU than it initially had. However, the EU’s institutional structure still resembles that of a specific supranational entity, less controlled by a classical trias politica but rather by a maintenance of a special institutional balance between the institutions, a balance between them and the Member States and individuals, and a balance between the Member States and individuals. In Chernobyl, for example, the maintenance of the special institutional balance resulted in the Court admitting an action for annulment brought by the European Parliament, despite the fact that the Treaties did not then explicitly provide for such (Case C-70/88, European Parliament v Council, paras 21–31). If the Court’s role in the EU’s institutional system were to be described in a single purpose, it would probably be the ‘maintenance and observance of the institutional balance laid down in the Treaties’ (Case C-70/88, European Parliament v Council, para. 26). Yet even more important is the Court’s role in ensuring that there is a complete system of judicial remedies (Parti écologiste ‘Les Verts’ v European Parliament, para. 23). The EU is ‘based on the rule of law, inasmuch as neither its Member States nor its institutions can avoid a review of the question whether the measures adopted by them are in conformity with the basic constitutional charter, the [Treaties]’ (Parti écologiste ‘Les Verts’ v European Parliament, in relation to the former EEC). The TEU makes it clear that the CJEU’s role is to ‘ensure that in the interpretation and application of the Treaties the law is observed (Art. 19(1) TEU). In fulfilling this role, the CJEU has become one of the most important institutions of the EU and in the European integration process (Everling, 1997, 398); some writers even assign to it the most important role in the integration process in Europe (Saurugger and Terpan, 2017, 208–16).

8  As the CJEU is part of the ‘Union’ referred to in Article 5 TEU, its mandate is limited to the powers conferred to it by the Member States—the principle of conferral, sometimes called the principle of attribution. Streinz has suggested that this means that it has to apply the principles of subsidiarity and proportionality to its actions (Streinz, 2011). In this sense, its jurisdiction would only be of a subsidiary nature, as it is the responsibility of the Member States to provide for remedies sufficient to ensure effective legal protection in the fields covered by Union law (Art. 19(1), second para., TFEU; Art. 47 Charter of Fundamental Rights). It is clear that the CJEU is bound by the principle of conferral (Art. 5(1) and (2) TEU; and Art. 1 Protocol on Subsidiarity and Proportionality) and can only act within the jurisdiction conferred on it by or by virtue of the TEU or the TFEU. Article 5(3) TEU, however, is aimed at the political institutions of the Union, as are Articles 2–7 of that Protocol on Subsidiarity and Proportionality. Article 8 of that Protocol confers specific jurisdiction on the CJEU ‘in actions on ground of infringement of the principle of subsidiarity by a legislative act, brought in accordance with the rules laid down in Article 263 TFEU by Member States, or notified by them in accordance with their legal order on behalf of their national parliament or a chamber thereof.’ It also confers standing on the Committee of the Regions to bring such an action against legislative acts for which the TFEU provides that it be consulted. The CJEU will look at the subsidiarity issue if it is raised in a case before it, but the track record of attempts to challenge EU acts on the basis of subsidiarity claims is not a successful one (eg The Queen v Secretary of State for Health, ex parte British American Tobacco (Investments) Ltd; The Queen, on the application of Vodafone Ltd and ors v Secretary of State for Business, Enterprise and Regulatory Reform; and Luxembourg v Parliament and the Council). This is not really surprising, as it is a matter of political judgment, involving the exercise of discretion. In cases in which the Union institutions have a discretion—and this is particularly wide in cases involving an appraisal of complex economic situations—the General Court and the Court of Justice will not substitute their own evaluation of the matter for that of the competent authority, but will restrict themselves to examining whether the evaluation of the competent authority contains a patent error—such as a distortion or manifest error of assessment of the facts—or constitutes a misuse of powers or abuse of process (eg Deuka Deutsche Kraftfutter GmbH v Einfuhr- und Vorratsstelle für Getreide und Futtermittel, para. 4; Matra SA v Commission, paras 24–25; Fédération des industries condimentaires de France (FICF) and ors v Commission, para. 94), or whether the authority did not clearly exceed the bounds of its discretion (eg Balkan-Import-Export GmbH v Hauptzollamt Berlin-Packhof, para. 8; Roquette Freres v Administration des Douanes, paras 19–20; Belgium v Commission, paras 67–68; Italian Republic v Council, paras 56–57), or whether the relevant procedural rules have been complied with (eg Remia BV and ors v Commission, para. 34; Fédération des industries condimentaires de France (FICF) and ors v Commission, para. 94).

9  When the CJEU is the author (see Arts 257, first para. (proposal to establish specialized courts attached to the General Court), 281, second para. (request to amend the CJEU Statute), TFEU; Art. 13 CJEU Statute (request to enable the appointment of assistant rapporteurs), and Art. 64 CJEU Statute (request for the adoption or amendment of the language arrangements applicable at the CJEU)), of a legislative act proposed for adoption under the ordinary legislative procedure (see Arts 289(4) and 294 TFEU, in particular, Art. 294(15)), it will have to take account of the procedures in the Protocol on Subsidiarity and Proportionality (see Arts 1 and 3 Protocol on Subsidiarity and Proportionality), so in that sense the principle of subsidiarity can be said to bind the CJEU. However, it does not appear that the CJEU will use subsidiarity in its reasoning where that issue has not been pleaded in a particular case, even if the judges might have the principle in the back of their minds (see Edward). The Court will be perfectly willing to use the principle of proportionality in its reasoning, though, as the mention of that principle in Articles 5(1) and (4) TEU and in Article 1 of the Protocol on Subsidiarity and Proportionality simply codifies the case-law in which the Court considered the proportionality of action by the political institutions as a major element in the assessment of the legality of such action (eg Bela Mühle Josef Bergmann KG v Grows-Farm GmbH & Co KG, para. 7; Atlanta Amsterdam BV v Produktschap voor Vee en Vlees, para. 15; Gebroeders Schulte AG and ors v Belgische Dienst voor Bedrijfsleven en Landbouw and ors, para. 15). Proportionality also plays a major role in the assessment of alleged justifications for barriers to free movement in the internal market (eg De Peijper, paras 15–18; Case 42/82, Commission v France, paras 51–62; Case 23/99, Commission v France, para. 48). Thus, as far as proportionality is concerned, it is submitted that Streinz’s view is correct.

10  The Court’s jurisdiction is fleshed out further in Article 19(3) TEU, which provides that it shall, in accordance with the Treaties, rule on actions brought by a Member State, an institution, or a natural or legal person; give preliminary rulings on the interpretation of Union law or the validity of acts adopted by the institutions, and rule in other cases provided for in the Treaties. These are further developed in Article 258 et seq TFEU.

11  When the CJEU has jurisdiction, the treaties have provided its courts with a wide mandate as a benchmark to decide these cases, as the CJEU has to ‘ensure that in the interpretation and application of the Treaties the law is observed’ (Art. 19(1), first sentence, TEU). This provision has been interpreted as a mandate to the Court not only to interpret existing legal provisions, but also to create and develop the law. The German Constitutional Court has prominently explained that ‘the Member States wished to provide the Community with a court which would have access to the many ways of finding law as it has been developed over centuries of common European legal tradition and culture’ (BverfGE 75, 223/243, Kloppenburg, translation KP). EU law has grown and grows organically: by from time to time referring to ‘in the present state of Community Law’ the Court of Justice itself recognizes that it may change in the future (in particular as a result of EU acts); this is not surprising given that the old EEC Treaty and even the current treaties are really frameworks or skeletons on which the clothes, flesh, and bones of the Community—and now the Union—have been placed by the adoption of regulations, directives, and decisions, as well as other acts.

12  In this sense, a distinction may be drawn between the creation and development of the law (see the interview with Rudolf Bernhard to illustrate how difficult this distinction is from a practical perspective in Rebasti and Purnhagen, 2007). The Court’s mandate to create law rests on the requirement to ensure the full effectiveness of EU rules (eg Francovich and Bonifaci v Italy, paras 33–34). As such, the Court creates legal rules only to the extent to which this is required for the effectiveness of (other existing) EU rules. Examples of the Court’s legal creations include the concept of direct effect (NV Algemene Transport- en Expeditie Onderneming van Gend & Loos v Nederlandse Administratie der Belastingen); development of the requirement that the EU must respect fundamental rights (Stauder v Stadt Ulm); the declaration of EU law’s supremacy (Costa v ENEL; Internationale Handelsgesellschaft); and the creation of (State) liability norms (Francovich and Brasserie du Pêcheur SA v Bundesrepublik Deutschland; The Queen v Secretary of State for Transport, ex parte Factortame Ltd and ors).

13  The CJEU’s mandate to develop the law largely rests on the doctrine of giving practical effect (effet utile) to the provision or act concerned. This doctrine, which is borrowed from international law, means ‘that the provisions of the Treaty are to be so interpreted that their purpose is, if possible, achieved, that they have a “practical value” and that their “effectiveness” can be developed. It can therefore be understood as meaning that preference should be given to the construction which gives the rule its fullest effect and maximum practical value’ (Kutscher, 1976 51). The same applies to EU secondary legislation. Thus existing rules need to be interpreted in the most appropriate forms and methods to ensure their effective functioning, account being taken of their aims (eg Fédération Chabonnière de Belgique v High Authority; Italy v High Authority; Germany v Commission (here text of the French version of the judgment is clearer: ‘si la Commission devait en tout cas se laisser orienter par la seule nécessité de promouvoir les échanges commerciaux avec les pays tiers, la conséquence serait que toute demande de dérogation devrait être satisfaite, ce qui priverait le tarif douanier commun de tout effet utile’ (rec. 1963, 269, 297); Royer, para. 73; Ordine degli Architetti delle Province di Milano e Lodi and ors v Comune di Milano, paras 5 2 and 55; Courage Ltd v Crehan, para. 26). In Land Rheinland-Pfalz v Alcan Deutschland GmbH the effet utile rationale was used (see Conway, 2013, 208) to justify repayment of a state aid even though, according to national law, the recipient had legitimate expectations in the lawful granting of the aid and was hence entitled to keep the aid. The Court held that the ‘Community provisions concerning State aid deprived of effectiveness’ (Land Rheinland-Pfalz v Alcan Deutschland GmbH, para. 37) if the business were to be allowed to keep it by relying on the national rule protecting its legitimate expect ations.

14  As there is no judicial body above the Court of Justice, it effectively decides on its own competence, and has exclusive jurisdiction to annul or declare invalid EU acts (see eg Foto-Frost v Hauptzollamt Lübeck, paras 15–18), as well as under Article 344 TFEU, in relation to disputes between Member States concerning the interpretation or application of the Treaties. The limits of the Court’s mandate to create and develop the law are legally set by these principles of conferral, subsidiarity, and proportionality. In addition, and more generally, the demarcation line for legal creation and development is set where the Court enters into the political sphere. While this is uncontested, it is difficult to draw a hard line between legal creation/development and political intervention (Weatherill 88). Furthermore, the acceptance of Court decisions by the judiciary and society at large acts as a practical limit to the judicial creation and development of the law; ultimately, the Member States could convene an Intergovernmental Conference to amend the Treaties—in that context they are Herren der Verträge (Masters of the Treaties); in all other circumstances it is the Court of Justice that is the Master of the Treaties (a position which it jealously guards, see eg Opinion 2/13, ECLI:EU:C:2014:2454).

15  While limited enforcement mechanisms at EU level do exist (see Art. 260 TFEU), the CJEU is ultimately dependent on the willingness of Member States’ institutions—including courts—to follow and enforce its judgments. Both aspects—not interfering in the political sphere and need for acceptance—result in the Court regularly accepting a wide margin of discretion for the Member States, Union institutions, and their administrations, in which the Court is reluctant to interfere. However, the Court has been prepared to find Member States in breach of their obligations under EU law where a national court flagrantly acts in breach of EU law (for example by refusing to make a reference to the Court of Justice when it is obliged to do so, as in Case C-416/17 Commission v France, paras 105–15). As part of its mission to ensure that the law is applied the Court has also started to interpret and apply extensively fundamental rights protection (Åklagaren v Hans Åkerberg Fransson) and consumer protection at EU level, which should enhance the acceptance of its case-law (Safjan, 2014, 143). It is worth noting that a failure by a national court, which is obliged to make a reference to the Court of Justice as there is no judicial remedy against the former’s ruling, to give reasons for refusal to make a reference will also fall foul of the European Convention on Human Rights (see Dhahbi v Italy). A failure to make a reference when obliged to do so may well lead to infringement proceedings being brought (see Case C-416/17, Commission v France), and/or an action for damages may, in appropriate circumstances, be brought before national courts.

16  In addition to references for preliminary rulings made by national courts, there are other types of actions that come before the Court. Infringement proceedings against a Member State brought by the Commission or by another Member State (Arts 258 or 259 TFEU) are particularly important. In certain specific cases the normal procedure may be accelerated (see Art. 108 TFEU (State aid); Art. 114(9) TFEU (improper use of the powers provided for under Art. 114 on harmonization); Art 348 TFEU (improper use of the powers provided for in Arts 346 and 347) TFEU); and Arts 38 and 82 Euratom Treaty (failure to comply with a Commission directive on protection against radioactivity or safeguards for nuclear materials)). Actions for annulment also form a major part of the CJEU’s workload (usually these will be under Art. 263 TFEU (which also applies to the Euratom Treaty by virtue of Art. 106a(1) Euratom), and they may include actions where the Court has been given jurisdiction by virtue of regulations in accordance with Article 261 TFEU; acts setting up European Union bodies, offices, and agencies may lay down specific conditions and arrangements concerning actions brought by natural or legal persons against acts of those bodies, offices, or agencies intended to produce legal effects against them (Art. 263, fifth para., TFEU).

17  Other important jurisdictions relate to actions for damages on the basis of non-contractual liability (Arts 268 and 340, second and third paras, TFEU); staff cases (Art. 270 TFEU and the Staff Regulations); Opinions under Article 218(11) TFEU; actions for failure to act under Article 265 TFEU; and appeals against judgments of the General Court (Art. 256(1), second sub-para., TFEU (the review procedure provided for in Art. 256(2) and (3) is at present otiose)). By virtue of Article 269 TFEU the Court has jurisdiction to decide on the legality of acts adopted by the European Council or by the Council pursuant to Article 7 TEU (concerning the procedural aspects of a determination of a risk of a breach, or of a serious and persistent breach, by a Member State of the values referred to in Art. 2 TEU). The Court also has certain jurisdiction in relation to actions brought by an European Free Trade Association (EFTA) State Party to the Agreement on the European Economic Area (‘EEA Agreement’) in relation to Commission decisions in merger cases (Art. 58 EEA Agreement and Art. 6(2) Protocol 24 to the EFTA Treaty; Declaration by the European Community on the rights for the EFTA states, second para.). The Court also has jurisdiction, exercised at first instance by the General Court in proceedings related to European intellectual property rights under specific regulations (Art. 262 TFEU).

18  Less frequently used jurisdiction includes: rulings under the Euratom Treaty on proposed agreements by Member States with third states, international organizations, or nationals of a third state and on agreements concluded by persons or undertakings with third states, international organizations, or nationals of a third state (Arts 103–105 Euratom); special proceedings under the Euratom Treaty (patent licensing (Arts 12 and 144(a), 17–22 Euratom Treaty), compulsory inspections (Art. 81 Euratom Treaty), sanctions for Treaty infringements by persons or undertakings (Arts 83, 144(b), and 145 Euratom Treaty), and accelerated infringement proceedings (Arts 38 and 82 Euratom Treaty); rulings under the EEA Agreement where the EEA Joint Committee has been unable to settle a dispute (Art. 111 EEA Agreement); disputes pursuant to an arbitration clause contained in a contract concluded by or on behalf of the EU, whether the contract be governed by public or private law (Art. 272 TFEU); disputes submitted to the Court of Justice under a special agreement between the Member States who are party thereto (Art. 273 TFEU); authorization of measures of search or constraint against the property of the European Union (Art. 1 Protocol on the Privileges and Immunities of the European Union), and data protection proceedings under Regulation 2018/1725.

19  The Court of Justice also has jurisdiction in proceedings against members of the Commission (Arts 245 and 247 TFEU), the Court of Auditors (Art. 286(6) TFEU), the CJEU (Arts 6 and 8 Protocol on the Statute of the CJEU), the European Ombudsman (Art. 228(2) TFEU), and members of the Executive Board of the European Central Bank (Art. 11.4 Protocol on the Statute of the European System of Central Banks and of the ECB). The CJEU can grant interim measures (Art. 278 TFEU and Art. 157 Euratom Treaty); consider a plea of illegality invoked in proceedings in which an act of general application adopted by an institution, body office, or agency of the EU is at issue (Art. 277 TFEU), and can act in various disputes relating to the European Investment Bank (Arts 271(a)–(c) TFEU) and the fulfilment by national central banks of obligations under the Treaties and under the Statute of the European System of Central Banks (ESCB) and the European Central Bank (Art. 271(d) TFEU).

20  While review by the Court of Justice is excluded in relation to Common Foreign and Security Policy and acts adopted thereunder (Art. 24(1), second sub-para., TEU; and Art. 275, first para., TFEU), it does have jurisdiction to monitor compliance with Article 40 TEU, and in actions for annulment brought under Article 263 TFEU challenging the legality of decisions that provide for restrictive measures against natural or legal persons adopted by the Council under Chapter 2 of Title V TEU (Art. 275, second para., TFEU). The Court also has competence to deliver an Opinion under Article 218(11) on whether an envisaged international agreement is compatible with the Treaties.

21  The CJEU is competent to review matters regarding judicial cooperation in criminal matters and in relation to police cooperation (Part Three, Title V, Chapters 4 and 5 TFEU, ie Arts 82–89 TFEU), but it has no power to review the validity or proportionality of operations carried out by police or other law enforcement services of a Member State or the exercise of the responsibilities incumbent upon Member States with regard to the maintenance of law and order and the safeguarding of internal security (Art. 276 TFEU). This review is left to the national legal systems of the Member States, and in appropriate cases to the European Court of Human Rights.

22  The role of the Court in the EU institutional system, its powers, and its case law have been subject to intensive scholarly literature in several academic domains (for a summary see eg Schepel and Blankenburg, 2001, 9). An all-encompassing treatment of these is an endeavour that is neither possible nor desirable in an encyclopaedia entry. However, the various treatments and evaluations of the case law of the Court and its role in the institutional system may be broken down into the clusters of those who support a stronger role of the Court and its case law and those who would like to see the Court exercising more restraint. Within these clusters the panorama is also different.

23  Those who agree with a strong role of the Court or who would like to give the Court an even stronger mandate in the development of the law view the Court from different angles. The Court would be the only EU institution with a clear integrationist agenda (Saurugger and Terpan, 2017, 208–16), the engine of European integration (Everling, 1997, 398–99), which drives EU integration without steering it (Ehlermann, 1992, 218; Mancini, 1989, 595; Weiler, 1993, 417). The law-creating function of the CJEU has been described as a necessary requirement to build a supranational legal order (Weiler, 1981, 267–68; Weiler, 1991, 2403). The wide mandate of the Court has been justified by the special role it has in response to the development of the EU legal system. Early EU law has been characterized as a fragmented system, which needed to assert itself in an area between national and international law (Lenaerts, 2013, 15–16). In such incomplete legal systems, non-Court institutions often lacked the regulatory potential they need to solve problems and/or are blocked by disputes over competences (Slaughter, 2003, 193; Petersmann, 1998–1999, 1). In the absence of other possibilities, the theory of constitutionalism assigns courts to be the ones who have the means to fill such regulatory gaps, creating a constitution of inter- or supranational law (Caruso, 2006, 29–30). It is within this concept that most supporters of a strong Court with wide-ranging judgments understand the Court. ‘The unwillingness- and unableness [sic] of Member States to fulfil their obligations to integrate via a political process was substituted for integration via judicial control’ (Purnhagen, 2013, 158; see, in relation to failures by the (then) Community legislature EU institutions, Pescatore, 1983). Others endow the Court with a strong role as its function would be to match EU law with societal change. Hence, its mandate would be to update existing legislation with societal evolution, both technical and social (AG Bobek in Confédération paysanne and ors v Premier ministre and Ministre de l’agriculture, de l’agroalimentaire et de la forêt, para. 100; Purnhagen, 2019, 1379), eg by responding to societal loss of meaning of traditional role models (AG Kokott in Association Belge des Consommateurs Test-Achats ASBL v Conseil des ministers, para. 63), or empower consumers to exercise political consumerism (AG Hogan in Organisation juive europénne et al v Ministre de l'Économie et des Finances, para. 51; Purnhagen, van Zeben, Oosterveer, and Ahlborn, 2020).

24  Those who would like to see the CJEU acting with more restraint describe the Court as activist (see, for assessments of this claim, Solanke 764; Grimmel 61–83), as a political actor (Schmidt), or as a vehicle for particular interest groups to pursue their agendas via Court judgments (Haltern, 2004, 177). More reluctantly, some have accused the Court of applying a legal method to reach its decisions which either lacked transparency and proper reasoning (Thiele, 2014, § 3, para. 27) or used teleological reasoning to widen its competences (Everling, 1994, 128, countering this critique). Others respond to the theories elaborated above that ascribe the Court the mandate to act more powerfully in certain areas. In particular, the theory of constitutionalism has been subject to criticism already since the beginning of the new millennium. Single voices in the literature have cautiously questioned whether in an EU legal system with an ever-growing body of law the narrative of judicial constitutionalisation would still hold value (Hunt, 2007, 155). This criticism, voiced by only a few scholars, gained momentum when a prominent academic and judge on the CJEU reflected on the merits of such criticism (Lenaerts, 2013, 16). Lenaerts proclaimed that, in the establishment phase of the EU, the Court indeed had filled the gaps of the EU constitution. This was a clear endorsement of the role the previously voiced theory of constitutionalism had provided to the Court. He moved on to explain that, in his opinion, the constitution had by now been established at EU level, proclaiming a paradigm shift at the Court; thus, after the constitution has been established, the Court now moves on into a more governing mode, paying more deference to the individual’s needs, and to Member State and EU desires (Lenaerts, 2013, 16). The more the EU legal system develops, the more the role of the judiciary changes from a ‘constructor’ or ‘creator’ of the law to an ‘applier’ (Purnhagen, 2013, 146–47). The most logical reason for such an increasingly restrained role of the Court would therefore be that in areas where competences are undisputedly assigned to the Member States, those Member States in fact start recapturing their role as political actors (Purnhagen, 2013, 158). In areas where the EU has established competences to shape politics via law, the Court’s jurisdiction likewise will be ‘less exclusive’ (Reich, 1992, 895).

25  Those who see the Court as an institution entrusted with the mandate to interpret EU law in a way that would match law with societal change saw themselves challenged with the criticism that they are barking up the wrong tree. The Court would be responsible for giving effect ‘to the policy choices made by the authors of the applicable Community rules’ (Arnull, 1999, 509). Indeed, Courts are seldom the correct addressee for deciding complex policy questions, as their mandate and expertise is too limited compared to the one of policy makers such as the European Parliament, the Council, or the Commission. Despite these insights, the history of judicial review in EU law is full of examples where policy makers refrained from taking political decisions hoping for a judicial solution. A Court cannot provide a balancing of different policy measures, comparable to a lawmaker. Unlike policy makers, courts are tied to the strict application of the respective judicial procedure, often a preliminary ruling, vested in answering a concrete question using the limited information available to solve the concrete case. Expectations placed upon the Court are hence often high, unrealistic and result in disappointment of what a respective judicial procedure is able to deliver (on the example of gender equality law, see Mancini and O’Leary, 1999, 353; on matching EU law with technological change, see Purnhagen, 2019). Indeed, in highly political areas, such as in the area of GMOs, the Court is well advised to stay even closer to the wording of the respective underlying provisions than usual, assigning the mandate for change to the respective institutions entrusted with policy making (Purnhagen and Wesseler, 2016, 156). However, as to the aforementioned legitimizing function, it can likewise be observed that the Court is willing to interpret existing rules more extensively in cases where rights to individuals are granted by the EU’s legal order (Lenaerts, 2013, 16). As a consequence, it has been observed that the Court moves from being a constitutional Court aiming to establish a supranational legal order, more into a Court, which, in the one hand, manages the diversity of Member States by exercising restraint, and, on the other, interprets existing individual rights in an expansionist manner (Purnhagen, 2020).

26  Judicial decisions by EU courts bind the parties involved in the dispute. However, the CJEU frequently cites past judgments to support its analysis and conclusions and also to demonstrate consistency in its approach—initially this was done silently without even referring to the earlier judgments at all. While there is no formal rule of binding precedent—in the English Sense of stare decisis—in particular a line of case-law can be said to make a position in law clear. Indeed, this was emphasized in the United Kingdom (UK)—when it was a Member State of the EU—in section 3(1) European Communities Act 1972, which obliged the UK courts—if not making a reference for a preliminary ruling—to determine cases in accordance with the principles laid down by and any relevant decision of the European Court of Justice. While the CJEU will usually follow its earlier case-law, it may change track if there is a very good reason for doing so (eg in SA CNL-Sucal NV v Hag AG). As observed above, failure by a Member State or one of its organs—such as a national court—to follow a settled line of case-law of the Court of Justice—or even a single judgment—may lead to infringement proceedings being brought by the Commission (eg Case C-416/17, Commission v France), and/or actions for damages being launched by individuals who have suffered loss through national acts or judgments that run counter to clear case-law of the Court of Justice. Indeed, the relevance of infringement proceedings for damages claims by individuals was already recognized long ago in Case 39/72, Commission v Italy (para. 11). With respect to damages claims, the Court clarified in Köbler that the requirement of a sufficiently serious breach in the sense of the requirements for non-contractual liability of Member States may be established where the national court issued a decision in manifest breach of the case law of the Court of Justice in the matter (Köbler v Republik Österreich, para. 56). The Court further stipulated in Traghetti that if a national court would give an existing ‘substantive or procedural rule of Community law a manifestly incorrect meaning, particularly in the light of the relevant case-law of the Court on the subject,’ or ‘interprets national law in such a way’, it would not be ‘inconceivable that a manifest infringement of Community law might be committed’ (Traghetti del Mediterraneo SpA v Repubblica Italiana, para. 35). A manifest infringement of EU law is even ‘presumed where the decision involved is made in manifest disregard of the case-law of the Court on the subject’ (Traghetti del Mediterraneo SpA v Repubblica Italiana, para. 43).

27  Judgments of the Court interpreting EU law state the law as it must be, or ought to have been, understood and applied from the time of its entry into force; they have thus effect ‘ex tunc’, and the interpretation pronounced has to be applied by the courts also to legal relationships which have arisen and been established before the date of the judgment on the request for interpretation, subject to any national procedural requirements—such as time limits—that fulfill the requirements of equivalence and effectiveness (see eg Amministrazione delle Finanze dello Stato v Denkavit Italiana Srl, para. 16; Amministrazione delle Finanze v Srl Meridionale Industria Salumi and ors, para. 9; Barra v Belgian State and ors, para. 11; as to equivalence and effectiveness, see eg Rewe-Zentralfinanz eG and ors v Landwirtschaftskammer für das Saarland, para. 5; Comet BV v Produktschap voor Siergewassen, para. 13; and Sante Pasquini v Istituto nazionale della previdenza sociale (INPS), paras 59–63). In exceptional circumstances, however, the Court may, on grounds of legal certainty, limit the effect in time of its judgments, the effect of the interpretation given is then ‘ex nunc’. Most of the very few cases in which the Court has done this involve interpretation given in the context of references for a preliminary ruling under (now) Article 267 TFEU (celebrated examples include Defrenne v Société Anonyme Belge de Navigation Aérienne SABENA, paras 71–75; Blaizot v University of Liège and ors, paras 30–35; Barber v Guardian Royal Exchange Assurance Group, paras 40–45; Administration des Douanes et Droits Indirects v Legros and ors, paras 28–36; Union royale belge des sociétés de football association ASBL and ors v Bosman, paras 139–46; and Association belge des Consommateurs Test-Achats ASBL v Conseil des ministers, paras 32–34). Exceptionally, the CJEU may also limit in time the effect of a judgment in infringement proceedings (eg Case 35/97, Commission v France, para. 19; Commission v United Kingdom, paras 91–96; Commission v Finland, paras 56–59; Case C-387/05, Commission v Italy, paras 57–60).

28  While, as noted above, a judgment in infringement proceedings finding that a Member State is in breach of its obligations because of a particular act or omission may be useful to a litigant seeking to challenge a national provision in the national courts, particularly in relation to a claim for damages (eg Case 39/72, Commission v Italy, para. 11; Commission v Hellenic Republic, para. 14; Case C-249/88, Commission v Belgium, para. 41), the litigant’s action rests on the incompatibility of the national provision with the directly effective provision of EU law concerned (Procureur de la République and Comité national de défense contre l’alcoolisme v Waterkeyn and ors, paras 15–16). Where the incompatibility found in infringement proceedings concerns a provision of EU law which is not directly effective, the obligations flowing from Article 4(3) TEU (duty of loyal cooperation) mean that the judgment of the CJEU is complied with, and the national court must apply the national law concerned in a manner which ensures this (Lenaerts, Maselis, and Gutman, 2014, 20).

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Select Documents

• Declaration by the European Community on the rights for the EFTA states (3 January 1994) [1994] OJ L1/1.

Select Cases