Introduction
The judgment of the Court of Justice of the European Union (CJEU) in Costa v ENEL (1964) is widely regarded as a foundational case in the development of European Union (EU) law. It is most commonly associated with establishing the doctrine of the supremacy, or primacy, of EU law over the national laws of Member States. However, the statement posed in the question suggests that this focus on supremacy understates the case's true constitutional importance. It proposes that the more fundamental achievement of Costa was the establishment of EU law as an autonomous and independent legal order. This essay will critically assess this statement. It will argue that the statement is correct; while the principle of supremacy is the most famous outcome of the case, it is a logical and necessary consequence of the Court’s more profound declaration that the EEC Treaty had created a new, distinct legal order. The establishment of this autonomous legal order is therefore the true, far-reaching constitutional significance of the Costa v ENEL judgment.
The Factual Background and Judgment in Costa v ENEL
The case arose from a relatively minor dispute in Italy. In 1962, the Italian government nationalised the electricity industry, creating the Ente Nazionale per l'Energia Elettrica (ENEL). Mr Flaminio Costa, a shareholder in a company that had been nationalised, refused to pay an electricity bill of 1,925 lire, arguing that the nationalisation law was contrary to several articles of the Treaty of Rome (EEC Treaty). The Italian court, the Giudice Conciliatore of Milan, made a preliminary reference to the CJEU under what is now Article 267 of the Treaty on the Functioning of the European Union.
The Italian government argued that the reference was inadmissible. It contended that an Italian court was obliged to apply Italian national law, and under the domestic constitutional principle of lex posterior derogat legi priori (a later law repeals an earlier one), the 1962 nationalisation act took precedence over the EEC Treaty, which had been ratified in Italy in 1957. This argument presented a direct challenge to the authority of Community law.
The CJEU rejected the Italian government’s position in a landmark judgment. The Court famously declared:
"By contrast with ordinary international treaties, the EEC Treaty has created its own legal system which, on the entry into force of the Treaty, became an integral part of the legal systems of the Member States and which their courts are bound to apply" (Case 6/64 Costa v ENEL [1964] ECR 585).
From this starting point, the Court reasoned that Member States had limited their sovereign rights, albeit within limited fields, and had created a body of law binding on both their nationals and themselves. This reasoning formed the bedrock for the principles that followed.
The Doctrine of Supremacy
The most immediate and widely discussed consequence of the Costa judgment was the establishment of the doctrine of supremacy. The CJEU held that law stemming from the Treaty, an independent source of law, could not be overridden by domestic legal provisions, "however framed, without being deprived of its character as Community law and without the legal basis of the Community itself being called into question" (Costa v ENEL, p. 594). In essence, where there is a conflict between a provision of national law and a directly applicable provision of EU law, the EU law provision must be given priority.
This principle is constitutionally radical. It demands that national courts set aside, or disapply, conflicting national law, even if that law is a fundamental part of the state's constitution or was passed after the EU law came into effect (Chalmers et al., 2019). The doctrine directly challenges traditional understandings of national sovereignty, particularly the principle of parliamentary sovereignty central to the UK's unwritten constitution. The practical effect is to ensure the uniform and effective application of EU law across all Member States, preventing any one state from unilaterally opting out of its obligations. For this reason, Costa is primarily taught and remembered as the case that established supremacy. However, to focus only on this aspect is to miss the fundamental legal reasoning that made it possible.
Beyond Supremacy: Establishing an Autonomous Legal Order
The statement in the question correctly identifies that the significance of Costa extends "far beyond" supremacy. The core of the CJEU’s judgment was not simply a declaration of a hierarchy of norms, but an explanation of the unique nature of the Community legal system itself. The Court’s assertion that the EEC Treaty had created its "own legal system" was revolutionary. This was not traditional international law, which typically governs relations between states and often requires incorporation into national law to be effective. Instead, the Court was describing a new, sui generis (of its own kind) legal order.
This new legal order is autonomous, meaning it is independent of the legal systems of the Member States while also being integrated within them. Its authority derives from the Treaties themselves, not from the constitutions of the individual Member States. This autonomy is evidenced by several features which the Court alluded to. Firstly, the subjects of this new legal order are not just the Member States, but also their nationals. This had been established in Van Gend en Loos (1963), which introduced the principle of direct effect, allowing individuals to rely on Treaty provisions before their national courts. Costa built directly upon this, confirming that if individuals were to have enforceable rights, there must be a system to ensure those rights were not nullified by national legislation.
Secondly, the creation of this legal order was based on the idea that Member States had voluntarily accepted a "permanent limitation of their sovereign rights" (Costa v ENEL, p. 594). This transfer of competence to Community institutions in specific fields meant that within those fields, the Community’s law had to be paramount. If it were not, the transfer of sovereignty would be meaningless and conditional, liable to be reversed by a simple act of a national parliament. Supremacy is, therefore, not an end in itself but a necessary condition for the existence of this autonomous legal order (Craig and de Búrca, 2020). Without supremacy, the "own legal system" described by the Court would disintegrate, as its application would depend on the goodwill of each Member State's legislature.
Therefore, the statement that Costa established the autonomy of EU law is a more accurate and profound assessment of its constitutional significance. The doctrine of supremacy is the most visible tool for protecting that autonomy, but the foundational concept is the existence of the autonomous system itself.
Critical Assessment of the Statement
In assessing the statement, it is clear that it presents a persuasive argument. To view Costa solely through the lens of supremacy is to see the symptom rather than the cause. The CJEU's reasoning was structural; it first defined the nature of the Community and its law, and from that definition, the necessity of supremacy followed logically. The Court was engaged in a process of constitutionalisation, creating a framework where the Treaty was not just an agreement between states but the constitution of a new legal entity (Weiler, 1991).
However, one could argue that separating the concepts of autonomy and supremacy is an artificial exercise. It is questionable whether one could exist without the other. An autonomous legal order with no mechanism for ensuring its precedence in cases of conflict would be practically ineffective. Conversely, a doctrine of supremacy without the underlying justification of a new, independent legal order would lack legitimacy and appear as a simple power grab by the CJEU. The two concepts are intrinsically linked and were developed by the Court as two sides of the same coin to ensure the effectiveness (effet utile) of Community law.
Nevertheless, the statement’s emphasis on the establishment of the autonomous legal order as the more fundamental contribution is compelling. The idea of a new legal order, with its own institutions, sources of law, and subjects, is a far more complex and significant constitutional development than the simple rule that one type of law trumps another. It reframed the entire relationship between the Member States and the Community, moving it from the realm of international cooperation to one of constitutional integration. Supremacy is the functional principle that makes this integrationist model work, but the model itself was the key innovation of Costa.
Conclusion
In conclusion, the statement that the constitutional significance of Costa v ENEL extends far beyond the doctrine of supremacy to the establishment of an autonomous legal order is a robust and accurate assessment. While the principle of supremacy is the case's most famous and perhaps most contested legacy, it was not created in a vacuum. It was the necessary and logical consequence of the CJEU’s more fundamental assertion that the Treaties had created a new and independent legal system, distinct from both international law and the domestic law of the Member States. This new legal order, based on a limitation of national sovereignty and conferring rights directly upon individuals, required a rule of priority to ensure its survival and uniform application. The doctrine of supremacy provided that rule. Therefore, while inextricably linked, it was the establishment of the autonomous legal order that represented the true constitutional shift, making Costa v ENEL a case of enduring and profound importance in the history of European integration.
References
Case 26/62 NV Algemene Transport- en Expeditie Onderneming van Gend & Loos v Nederlandse Administratie der Belastingen [1963] ECR 1.
Case 6/64 Flaminio Costa v ENEL [1964] ECR 585.
Chalmers, D., Davies, G. and Monti, G. (2019) European Union Law: Text and Materials. 4th edn. Cambridge: Cambridge University Press.
Craig, P. and de Búrca, G. (2020) EU Law: Text, Cases, and Materials. 7th edn. Oxford: Oxford University Press.
Weiler, J.H.H. (1991) 'The Transformation of Europe'. The Yale Law Journal, 100(8), pp. 2403-2483.
