The EU Legal Order and the Relationship Between EU Law and National Law: Primacy, Direct Effect, and Constitutional Authority

The EU Legal Order and the Relationship Between EU Law and National Law: Primacy, Direct Effect, and Constitutional Authority

Introduction

The European Union is founded on international treaties, but its legal system operates in a way that cannot be explained by the ordinary rules governing relations between sovereign states. EU law does not merely create obligations between governments. Under conditions established by the Treaties and interpreted by the Court of Justice of the European Union (CJEU), it can confer rights on individuals, impose duties on public authorities, influence national legislation, and determine how domestic courts must resolve disputes.

This distinctive legal structure is one of the defining characteristics of European integration. A rule adopted at Union level may become relevant in a national courtroom, an administrative proceeding, a commercial transaction, or a dispute between an individual and a public authority. A national judge may be required to apply an EU provision, interpret domestic legislation consistently with it, or decline to apply a conflicting national rule. In certain circumstances, an individual may rely directly on EU law to obtain judicial protection.

Three principles are central to understanding this relationship: primacy, direct effect, and effective judicial protection. They are connected, but they perform different legal functions. Primacy addresses conflicts between EU law and national law. Direct effect concerns whether a provision of EU law can itself be relied upon before a national court. Effective judicial protection ensures that rights arising under EU law can be enforced through judicial procedures that are genuinely capable of protecting them.

These principles have developed through the Treaties and the case law of the CJEU. They have also generated a continuing constitutional debate. The Court of Justice regards the primacy of EU law as necessary to preserve the autonomy, uniformity, and effectiveness of the Union legal order. National constitutional courts, meanwhile, have considered how that principle relates to constitutional supremacy, democratic authority, the protection of fundamental rights, and the limits of powers conferred on the Union.

The relationship is therefore not adequately described as a simple hierarchy in which European institutions stand above national governments. The Union possesses only the competences conferred upon it by the Member States through the Treaties. Yet, within the scope of those competences, EU law has legal effects that national authorities and courts are required to respect. The resulting system combines supranational authority with continuing national constitutional responsibility.

This article examines how that system works: how EU law enters national legal orders, when individuals may invoke it, what national courts must do when domestic rules conflict with it, and how the CJEU and national constitutional courts negotiate the boundaries of constitutional authority.

1. The Distinctive Relationship Between EU Law and National Law

The starting point is the constitutional structure of the European Union. The EU is established by treaties concluded by its Member States. Those treaties define its institutions, objectives, competences, legislative procedures, and judicial system. In this respect, the Union has its origins in international law.

However, the legal consequences of EU membership extend beyond the traditional model of international cooperation. In an ordinary international organisation, treaty obligations generally bind states at the international level. Their domestic effect depends substantially on the constitutional arrangements of each participating state. The EU legal order developed differently: certain rules of Union law can operate within national legal systems and be invoked by individuals before domestic courts.

The Court of Justice articulated this distinctive character in Van Gend en Loos v Nederlandse Administratie der Belastingen (Case 26/62). The dispute concerned a customs duty imposed by the Netherlands on the importation of a chemical product from Germany. The importing company argued that the charge violated the Treaty of Rome’s prohibition on increasing customs duties between Member States.

The Dutch authorities maintained, in substance, that the relevant Treaty provision created an obligation between states rather than a right that a private company could enforce in court. The Court rejected that narrow understanding. It described the Community as a new legal order of international law for whose benefit the states had limited their sovereign rights, albeit within limited fields, and recognised that individuals could be subjects of that legal order.

The significance of the judgment was constitutional. The Treaty was not simply an agreement that governments could invoke against one another. At least some of its provisions were capable of creating rights for individuals, which national courts were required to protect.

This development did not mean that every provision of EU law automatically became directly enforceable by every individual. Nor did it mean that the Union acquired unlimited legislative authority. It established a different proposition: the legal effects of Union law cannot be determined solely by reference to the traditional distinction between international obligations and domestic legislation. They must also be understood through the autonomous principles and judicial mechanisms of the EU legal order.

The Treaty framework now expressly recognises several elements of this relationship. Article 4(3) of the Treaty on European Union (TEU) establishes the principle of sincere cooperation, requiring the Union and Member States to assist one another in carrying out Treaty obligations. Article 19 TEU requires Member States to provide remedies sufficient to ensure effective legal protection in fields covered by Union law. Article 267 of the Treaty on the Functioning of the European Union (TFEU) enables national courts to obtain authoritative interpretations of EU law from the CJEU.

Together, these provisions create a system in which national authorities and courts are not merely external observers of European law. They are essential participants in its implementation and enforcement.

2. Primacy of EU Law: The Principle That Resolves Conflicts

2.1. The origin of primacy: Costa v ENEL

The principle of primacy, sometimes called supremacy, establishes that where a valid rule of EU law conflicts with a rule of national law, the EU rule must prevail within the scope of Union law.

The leading judgment is Flaminio Costa v ENEL (Case 6/64). The dispute arose from Italy’s nationalisation of its electricity industry. Mr Costa, an Italian lawyer and electricity consumer, challenged an electricity bill on the ground that the nationalisation legislation conflicted with provisions of the Treaty establishing the European Economic Community.

The Italian Government argued that the national legislation was adopted after the Treaty had entered into force and should therefore prevail under the ordinary domestic principle that a later statute may override an earlier one. The Court of Justice rejected that approach.

Its reasoning rested on the nature of the Community legal order. By establishing a Community of unlimited duration, possessing its own institutions, legal personality, legal capacity, and powers derived from limitations of sovereignty, the Member States had accepted a legal system that could not be displaced unilaterally by subsequent domestic legislation. If each Member State could override Community law through later national legislation, the uniformity and effectiveness of the common legal system would be undermined.

The principle was therefore not merely a rule for resolving chronological conflicts between two statutes. It was a structural requirement of the Community legal order.

The importance of Costa v ENEL lies in its rejection of the proposition that a Member State may determine unilaterally whether and when its domestic law will prevail over a rule of Union law. Membership entails obligations that cannot be neutralised by ordinary national legislative action.

2.2. Primacy and national constitutional provisions

The Court subsequently clarified that primacy is not confined to conflicts with ordinary legislation.

In Internationale Handelsgesellschaft (Case 11/70), the dispute concerned the validity of an EU agricultural regulation requiring an export licence and the forfeiture of a deposit if the exporter failed to fulfil the relevant obligation. A German company challenged the arrangement, arguing that it violated fundamental rights protected by the German Basic Law.

The Court held that the validity and effect of EU law could not be affected by allegations that it conflicted with national constitutional rules. If the validity of a Union measure depended on the constitutional standards of individual Member States, its uniform application would become uncertain and fragmented.

The judgment did not mean that fundamental rights were irrelevant to the EU legal order. On the contrary, the Court recognised that fundamental rights form part of the general principles of EU law, drawing inspiration from the constitutional traditions common to the Member States and international human rights instruments. The point was that the protection of fundamental rights had to be secured within the Union legal system rather than through unilateral national standards used to invalidate Union measures.

Today, this development is reflected in Article 6 TEU and the Charter of Fundamental Rights. The Charter has the same legal value as the Treaties, and fundamental rights are binding on the Union institutions and, within the scope of Article 51 of the Charter, on Member States when they implement or otherwise act within the scope of EU law.

The result is a constitutional relationship with two connected dimensions: EU law claims primacy within its field of application, while the Union itself is bound by fundamental rights and the principles of its own constitutional order.

2.3. The duty of national courts to disapply conflicting law: Simmenthal

A particularly important practical question remained: what must a national court actually do when it identifies a conflict between EU law and national legislation?

The Court addressed this in Amministrazione delle Finanze dello Stato v Simmenthal (Case 106/77).

Simmenthal, an Italian company, challenged a charge imposed on imported beef products. The charge was considered incompatible with Community law. The Italian procedural framework raised a difficulty: a national court might have to wait for the Constitutional Court to declare the conflicting legislation unconstitutional before refusing to apply it.

The Court of Justice rejected the need for such a delay. It held that every national court, within its jurisdiction, must give full effect to EU law and must therefore set aside any conflicting provision of national law, whether adopted before or after the relevant EU rule.

The national court must be able to do so immediately, without waiting for the legislature to repeal the national provision or for a constitutional court to invalidate it.

This distinction is fundamental. Primacy does not necessarily mean that the national statute disappears from the domestic statute book. The national court’s immediate obligation is to disapply the conflicting rule in the case before it, to the extent necessary to give effect to applicable EU law.

The national rule may remain formally part of the national legal system, but it cannot govern the dispute where its application would contradict a directly effective EU provision.

The principle also protects the institutional position of ordinary national courts. A judge does not need special constitutional jurisdiction to give effect to EU law. The obligation follows from the national court’s responsibility to apply the law governing the dispute.

2.4. Primacy and interim judicial protection: Factortame

The practical force of primacy was further demonstrated in R v Secretary of State for Transport, ex parte Factortame (Case C-213/89).

The case arose from the United Kingdom’s Merchant Shipping Act 1988, which introduced nationality, residence, and other conditions for registration of fishing vessels. Spanish-owned fishing companies argued that the legislation discriminated against them and restricted rights protected by Community law.

The House of Lords referred questions to the Court of Justice. A central issue was whether an English court could grant interim relief suspending the operation of national legislation where doing so was necessary to protect rights claimed under Community law.

At the time, domestic procedural doctrine restricted the availability of such relief against the Crown. The Court of Justice held that a national court must be able to grant interim protection where necessary to ensure the full effectiveness of the eventual judgment on EU law rights.

The case illustrates that primacy is not confined to the final resolution of a legal dispute. It may also require national procedural rules to permit effective interim protection. A right that exists only on paper, but cannot be protected before irreversible harm occurs, may not receive effective judicial protection.

Factortame is particularly significant because it demonstrated that EU law could require a national court to set aside the practical operation of an Act of Parliament in proceedings before it. It did not establish that the CJEU could repeal or formally invalidate an Act of Parliament within the United Kingdom’s domestic constitutional system. Rather, the national court was required to give priority to the applicable Community law obligation in deciding the case.

2.5. What primacy does—and does not—mean

The principle can be misunderstood if described too broadly.

Primacy does not mean that EU law governs every area of national life. The Union has only the competences conferred upon it by the Member States under the Treaties. Article 5 TEU establishes the principles of conferral, subsidiarity, and proportionality. Competences not conferred upon the Union remain with the Member States.

Nor does primacy mean that every provision of EU law can automatically be invoked by an individual in every dispute. Whether a person can rely directly on a particular provision is a separate question of direct effect. Where a provision lacks direct effect, other mechanisms—such as consistent interpretation, infringement proceedings, or state liability—may still be relevant.

Finally, primacy does not mean that national law is generally invalid whenever it differs from EU law. A conflict must arise within the field governed by applicable Union law. A national rule concerning a matter outside the scope of EU law is not displaced merely because EU law exists in a related area.

The doctrine is therefore best understood as a rule of priority within the Union’s sphere of competence, rather than as a general transfer of unlimited constitutional authority to the European institutions.

3. Direct Effect: When Individuals Can Rely on EU Law

3.1. The principle established in Van Gend en Loos

Primacy explains which rule prevails when EU law conflicts with national law. Direct effect addresses a different question: can an individual rely on a particular provision of EU law before a national court?

The doctrine was established in Van Gend en Loos. The Court held that a Treaty provision could create rights for individuals where its wording, nature, and structure made it sufficiently clear and unconditional.

The classic formulation is that a provision must be sufficiently clear and precise and must not be dependent on further implementing measures or discretionary action before it can be relied upon by an individual.

These requirements are not a mechanical checklist applied without regard to context. The Court examines the substance of the provision, its legal setting, and whether a court can apply it without having to make policy choices reserved to the legislature or another authority.

A provision may therefore have direct effect even if it requires some interpretation. Legal provisions are rarely self-executing in the sense of being entirely free from interpretative questions. The essential issue is whether the legal obligation is sufficiently determinate for a court to identify and enforce it.

Direct effect transformed the role of individuals in the EU legal order. They became not merely beneficiaries of political cooperation between governments, but potential claimants able to enforce certain Union rights through domestic judicial proceedings.

3.2. Direct effect and direct applicability are not identical

The terms direct effect and direct applicability are sometimes used interchangeably in informal discussion, but they describe different legal concepts.

Direct applicability concerns whether an EU rule becomes part of the legal systems of Member States without requiring national transposition. Article 288 TFEU expressly provides that regulations are directly applicable in all Member States.

Direct effect concerns whether a particular provision can be relied upon before a court or other competent authority.

A regulation may be directly applicable but not every provision within it will necessarily satisfy the conditions for direct effect. Some provisions may require further administrative measures, contain broad policy objectives, or leave substantial discretion to national authorities.

Conversely, a provision of a directive may, in certain circumstances, have direct effect even though directives are not directly applicable in the same way as regulations. This distinction is particularly important when considering the relationship between EU legislation and national implementing measures.

3.3. Direct effect of Treaty provisions

Treaty provisions may have direct effect where their content satisfies the relevant requirements.

The doctrine has developed well beyond the customs-duty provision considered in Van Gend en Loos. The Court has recognised direct effect in relation to various Treaty rules, including certain provisions concerning free movement, competition, and non-discrimination.

For example, Article 157 TFEU, which requires Member States to ensure equal pay for male and female workers for equal work or work of equal value, has been recognised as capable of producing direct effect. In Defrenne v SABENA (Case 43/75), the Court considered the enforceability of the equal-pay principle in proceedings involving a female flight attendant who argued that she had received less favourable pay than male colleagues.

The case demonstrated that certain Treaty obligations can operate not only against public authorities but also in disputes involving private parties. This is particularly important in fields where EU law regulates relationships within the private economy.

Direct effect is therefore not limited to rights against the state. The possibility of horizontal direct effect depends on the source and nature of the provision concerned.

3.4. Direct effect of regulations

Regulations are binding in their entirety and directly applicable in all Member States under Article 288 TFEU. They do not require national legislation to transform them into domestic law.

Where a provision of a regulation is sufficiently clear, precise, and unconditional, an individual may ordinarily rely on it before a national court.

National authorities cannot treat a regulation as though it were merely a policy instruction awaiting domestic approval. They must apply it as part of the applicable legal framework.

Nevertheless, the fact that a regulation is directly applicable does not mean that every provision necessarily creates an individual right. Some provisions are addressed to institutions or require further administrative implementation. The legal effect of the specific provision must therefore be assessed.

3.5. Direct effect of decisions

Article 288 TFEU also provides that a decision is binding in its entirety. Where a decision specifies those to whom it is addressed, it is binding only on them.

A decision addressed to a Member State may, depending on its wording and content, be relied upon by individuals against that state where the relevant obligation is sufficiently clear, precise, and unconditional.

In Grad v Finanzamt Traunstein (Case 9/70), the Court recognised that provisions of a decision could produce direct effects. The fact that Article 288 does not expressly use the same language for decisions as it does for regulations does not prevent a sufficiently determinate obligation from being judicially enforceable.

The analysis remains provision-specific: the binding nature of the decision is important, but the individual provision must still be capable of judicial application.

3.6. Direct effect of directives: A distinctive and limited doctrine

Directives present a more complex situation.

Under Article 288 TFEU, a directive is binding, as to the result to be achieved, upon each Member State to which it is addressed, while leaving national authorities the choice of form and methods. Directives normally require national transposition.

The Court has nevertheless recognised that individuals may rely on certain provisions of a directive against the state when the Member State has failed to implement it correctly or within the prescribed period.

The leading case is Van Duyn v Home Office (Case 41/74). The Court accepted that a sufficiently clear and unconditional provision of a directive could have direct effect. Otherwise, a Member State could benefit from its own failure to fulfil its obligations by preventing individuals from relying on the directive.

The conditions are generally that:

• the transposition deadline has expired;
• the Member State has failed to implement the directive, or has implemented it incorrectly;
• the particular provision relied upon is sufficiently clear and precise; and
• the provision is unconditional, in the sense that its application does not depend on further discretionary measures.

The effect is not to convert the directive into a regulation. Rather, it prevents the defaulting state from relying on its own failure to implement the directive as a reason to deny individuals the rights that the provision confers.

Directives therefore occupy a distinctive position. They are binding on Member States as to the result to be achieved, but their provisions may become judicially enforceable against the state where the relevant conditions are satisfied.

3.7. The absence of horizontal direct effect of directives

A central limitation is that directives do not, as a general rule, have horizontal direct effect. This means that an individual cannot ordinarily rely on an unimplemented or incorrectly implemented directive, by itself, to impose an obligation on another private individual or private company.

The leading authority is Marshall v Southampton and South-West Hampshire Area Health Authority (Case 152/84). Ms Marshall, a dietician employed by a public health authority, was required to retire at an age at which male employees were permitted to continue working. She relied on the Equal Treatment Directive, which prohibited discrimination on grounds of sex in employment.

The Court recognised that the relevant directive provision could be invoked against the state. It nevertheless held that a directive could not of itself impose obligations on an individual and could not therefore be relied upon as such against a private employer.

The Court confirmed this approach in Faccini Dori v Recreb (Case C-91/92). The dispute concerned a consumer who sought to rely on a directive concerning contracts negotiated away from business premises. The Court held that, even after the implementation deadline had expired, the directive could not itself impose obligations on another private party.

The distinction is important because directives are addressed to Member States. Their legal structure differs from that of regulations, which are directly applicable under Article 288 TFEU. If directives could routinely impose obligations directly on private parties without national transposition, the allocation of responsibility established by Article 288 would be substantially altered.

This limitation can create difficult situations. An individual may possess a right that the Member State was required to protect through national legislation, yet may be unable to rely directly on the directive against a private employer, company, landlord, or contracting party. EU law has developed alternative mechanisms to reduce this enforcement gap, particularly consistent interpretation and state liability.

3.8. The meaning of the state: The emanation of the state doctrine

The distinction between vertical and horizontal direct effect raises another question: what counts as the state?

A Member State cannot avoid its obligations simply by assigning public functions to a separate legal entity or organising a public service through an institution that has its own legal personality. The Court has therefore developed a broad approach to identifying bodies against which an individual may invoke a directive.

In Foster v British Gas (Case C-188/89), the dispute concerned employees of British Gas, a corporation that had been privatised after having previously operated as a statutory public undertaking. The employees sought to rely on an EU directive concerning equal treatment in employment.

The Court considered whether the corporation could be treated as an emanation of the state. It identified characteristics including the performance of a public service under state authority and the possession of special powers beyond those normally applicable in relations between private individuals.

The approach was clarified in Farrell v Whitty (Case C-413/15). The Court explained that a body may fall within the concept of the state where it has been entrusted by a Member State with a task in the public interest and, for that purpose, possesses special powers, or where it is subject to the authority or control of a public authority. The relevant criteria are not necessarily cumulative in the rigid sense suggested by some earlier readings of Foster.

The doctrine is functional rather than purely formal. The decisive question is not simply whether an organisation is legally classified as a public authority under domestic law. It is whether, in the circumstances identified by the Court, the organisation is sufficiently connected to the state or entrusted with public responsibilities and powers to justify treating it as part of the state for the purposes of enforcing the directive.

This matters in sectors such as healthcare, public transport, utilities, education, and other services in which public responsibilities may be performed by statutory bodies, publicly controlled companies, or private entities exercising delegated functions.

The doctrine does not mean that every company providing a service of public importance becomes an emanation of the state. The legal criteria must be examined in the particular case.

3.9. Why a directive cannot create obligations for individuals through indirect means

The prohibition on horizontal direct effect also limits the use of indirect interpretation. A national court must interpret domestic law consistently with EU directives where possible, but that obligation does not authorise the court to rewrite national legislation or create obligations for private parties in a manner that effectively gives the directive horizontal direct effect.

The Court has recognised that the obligation of consistent interpretation is subject to general principles of law, including legal certainty and non-retroactivity. A national court cannot interpret domestic law contra legem, meaning in a way that contradicts the clear meaning of the national provision.

Nor may an unimplemented directive, by itself, determine or aggravate the criminal liability of an individual. The legality of criminal offences and penalties requires particular protection against judicial creation of liability through an expansive interpretation of an EU directive.

The boundary is therefore important: indirect effect seeks to make national law compatible with EU obligations, but it cannot be used as a device to circumvent the legal limits on the direct effect of directives.

4. Consistent Interpretation: The Indirect Effect of EU Law

4.1. The duty to interpret national law consistently

The absence of horizontal direct effect does not mean that directives become irrelevant in disputes between private parties. The Court has developed the principle of consistent interpretation, sometimes called indirect effect.

Under this principle, national courts must interpret domestic law, so far as possible, in the light of the wording and purpose of applicable EU directives. The objective is to achieve the result intended by the directive without disregarding the national legal system’s own rules of interpretation.

The principle was developed in Von Colson and Kamann v Land Nordrhein-Westfalen (Case 14/83). The case concerned two women who had applied for positions in a prison but were rejected on grounds of sex. The national court found discrimination but considered that domestic law provided only limited compensation.

The Court of Justice held that national courts must interpret and apply domestic legislation adopted to implement a directive in a way that achieves the directive’s intended result. The directive required effective sanctions for discrimination, and the national court had to consider the relevant domestic provisions in that light.

The doctrine was further developed in Marleasing (Case C-106/89). A Spanish company sought a declaration that another company’s founding contract was void under national civil law. The dispute arose in a field governed by an EU company-law directive that limited the grounds on which a company’s formation could be declared invalid.

The Court held that the national court was required to interpret domestic law, whether adopted before or after the directive, in the light of the directive’s wording and purpose. The obligation was not confined to national provisions expressly enacted to implement the directive.

This significantly broadened the practical influence of EU law. A directive may affect the interpretation of domestic legislation even where the dispute is between private parties and the directive itself cannot be invoked horizontally.

4.2. The limits of consistent interpretation

The duty is substantial, but it is not unlimited.

National courts must use the interpretative methods recognised by their domestic legal systems, taking account of the whole body of national law and applying methods of interpretation that are compatible with the directive’s objectives. However, they are not required to adopt an interpretation that is impossible under national law.

The prohibition on interpretation contra legem protects legal certainty and the separation of judicial and legislative functions. Courts interpret legislation; they cannot simply replace it with a different rule because an EU directive would have required the legislature to enact that rule.

There are also limits arising from the temporal application of directives and from the general principles of EU law. A directive cannot be used to impose or aggravate criminal liability on an individual where national legislation does not provide a sufficiently clear legal basis for that liability.

Consistent interpretation is therefore a powerful means of ensuring the effectiveness of EU law, but it remains an interpretative obligation rather than an unlimited judicial power to reconstruct domestic legislation.

5. State Liability: Compensation for Breaches of EU Law

5.1. The principle established in Francovich

Even where direct effect and consistent interpretation cannot provide an effective remedy, an individual may be entitled to compensation from a Member State for damage caused by its breach of EU law.

The principle of state liability was established in Francovich and Bonifaci v Italian Republic (Joined Cases C-6/90 and C-9/90).

The dispute concerned an EU directive requiring Member States to establish protection for employees whose employers became insolvent. Italy failed to implement the directive within the prescribed period. Employees who had not received their wages sought compensation from the state.

The Court held that the principle of state liability forms part of the EU legal order. The effectiveness of Union law would be weakened if individuals could not obtain compensation where a Member State’s breach caused them loss.

The Court initially identified three conditions:

1. The result prescribed by the directive must entail the grant of rights to individuals.
2. The content of those rights must be identifiable on the basis of the directive’s provisions.
3. There must be a causal link between the Member State’s breach and the loss or damage suffered.

The significance of Francovich was broader than the particular employment dispute. It established that Member States may incur financial responsibility towards individuals for violations of EU obligations.

5.2. The general conditions developed in Brasserie du Pêcheur and Factortame

The Court subsequently clarified the doctrine in Brasserie du Pêcheur and Factortame (Joined Cases C-46/93 and C-48/93).

The principle was extended beyond the failure to transpose directives. State liability may arise from breaches of EU law attributable to any branch of the state, including the legislature, executive, and judiciary, subject to the conditions established by the Court.

The general conditions are:

• The EU rule infringed must be intended to confer rights on individuals.
• The breach must be sufficiently serious.
• There must be a direct causal link between the breach of the state’s obligation and the damage sustained by the injured party.

Whether a breach is sufficiently serious depends on the circumstances. Relevant considerations include the clarity and precision of the rule infringed, the degree of discretion left to national authorities, whether the infringement was intentional or involuntary, whether any error of law was excusable, and whether the EU institutions contributed to the adoption or maintenance of the national measure.

Where a Member State has no discretion, or very limited discretion, a sufficiently serious breach may be established more readily. Where the relevant rule leaves a broad margin of discretion, the seriousness of the breach requires a more contextual assessment.

State liability is not automatic whenever national law is found incompatible with EU law. The claimant must establish the relevant conditions, including the required causal connection and damage.

5.3. Liability arising from judicial decisions

The principle may also apply to breaches attributable to national courts of last instance, although the threshold is particularly demanding.

In Köbler v Austria (Case C-224/01), a university professor sought a salary supplement based on length of service. The Austrian administrative court refused to count certain service in other Member States, and the dispute eventually raised the question of state liability for a decision of a court against whose judgments there was no ordinary judicial remedy.

The Court confirmed that the principle of state liability can apply to judicial decisions, but only in exceptional circumstances where the court has manifestly infringed the applicable EU law.

This approach recognises two constitutional interests. Individuals must not be left without protection where a final judicial decision seriously breaches EU law, but judicial independence and legal certainty require that state liability should not become a routine means of challenging every alleged judicial error.

5.4. The function of state liability within the EU legal order

State liability complements primacy, direct effect, and consistent interpretation.

Primacy ensures that conflicting national law does not prevail over applicable EU law. Direct effect allows individuals to rely on certain EU provisions. Consistent interpretation seeks to align national law with EU obligations. State liability provides a compensatory remedy where a breach has caused loss and the relevant legal conditions are met.

These mechanisms are not interchangeable. A claimant may seek the disapplication of a national rule, an interpretation of domestic legislation consistent with a directive, or compensation for damage already caused. The appropriate route depends on the nature of the breach, the provision relied upon, the procedural circumstances, and the remedy sought.

The overall purpose is to ensure that Member States cannot make EU obligations practically ineffective through non-compliance.

6. National Courts as Courts of EU Law

6.1. The decentralised enforcement of EU law

The EU does not have a general system of first-instance courts operating throughout every Member State to resolve ordinary disputes involving Union law. Instead, much of the day-to-day application of EU law takes place before national courts.

A national court hearing a dispute about employment, taxation, consumer rights, competition, immigration, environmental protection, public procurement, or commercial activity may have to interpret and apply EU legislation. It may also have to determine whether a national measure complies with the Treaties or with a directly applicable regulation.

This creates a distinctive judicial arrangement. National courts remain part of their domestic judicial systems, but when applying EU law they also perform an essential function within the Union’s legal order.

The arrangement is sometimes described as decentralised enforcement. The CJEU provides authoritative interpretations of EU law and determines the validity of Union acts within its jurisdiction, while national courts apply those interpretations to the facts and resolve the underlying disputes.

This division of judicial responsibility is necessary because EU law governs a wide range of legal relationships across many Member States. A centralised European court system could not realistically hear every dispute involving Union law. National courts provide the ordinary judicial infrastructure through which EU rights and obligations are enforced.

6.2. The preliminary ruling procedure under Article 267 TFEU

The principal mechanism connecting national courts with the CJEU is the preliminary ruling procedure under Article 267 TFEU.

A national court may refer a question to the CJEU where it considers that an interpretation of EU law is necessary to decide the case before it. It may also refer questions concerning the validity of acts adopted by EU institutions, bodies, offices, or agencies.

The procedure is not an appeal from a national court to a European court. The CJEU does not ordinarily take over the national proceedings or decide the entire dispute. It answers the EU law question, after which the national court applies that answer to the facts and gives judgment.

For example, a national court may be uncertain whether a provision of a consumer-protection directive applies to a particular contractual arrangement. It may ask the CJEU to interpret the relevant provision. The CJEU provides the authoritative interpretation, while the national court determines whether the contract falls within that interpretation and what remedy follows under applicable national law.

The procedure has two principal functions:

1. Uniform interpretation: it reduces the risk that the same EU provision will be interpreted differently by courts in different Member States.
2. Judicial cooperation: it enables national courts to obtain authoritative guidance on the meaning or validity of EU law when resolving disputes.

The Court has repeatedly described Article 267 as a central element of the judicial system established by the Treaties. It helps preserve the consistency, effectiveness, and autonomy of Union law. EUR-Lex+1

6.3. When a national court must refer a question

Article 267 distinguishes between courts that may refer questions and courts against whose decisions there is no judicial remedy under national law.

A lower national court generally has discretion to make a reference if it considers that a ruling is necessary to resolve the dispute. A court of last instance is, in principle, required to refer a relevant question of interpretation or validity to the CJEU.

There are recognised exceptions. A court of last instance need not refer a question where:

• the question is irrelevant to the resolution of the dispute;
• the CJEU has already interpreted the relevant EU provision in a way that resolves the issue; or
• the correct interpretation is so clear that there is no reasonable doubt, applying the criteria established in the Court’s case law.

The third exception is commonly associated with CILFIT (Case 283/81) and the doctrine of acte clair. It is not enough for the national court simply to believe that its preferred interpretation is obvious. It must consider the specific characteristics of EU law, its multilingual nature, the context and purpose of the provision, and the risk of divergent interpretations across Member States.

In Consorzio Italian Management and Catania Multiservizi (Case C-561/19), the Court revisited the conditions governing the obligation of courts of last instance to refer questions. It reaffirmed that the acte clair exception must be assessed carefully and that a final court must be able to explain why the interpretation is sufficiently clear to exclude reasonable doubt. EUR-Lex+1

The obligation to refer is particularly important where the validity of a Union act is challenged. National courts cannot themselves declare an EU act invalid. Under the principles developed in Foto-Frost (Case 314/85), the CJEU has exclusive jurisdiction to declare an EU act invalid. A national court that considers a validity challenge well-founded must refer the matter to the Court rather than independently invalidating the Union measure.

6.4. The authority of preliminary rulings

A preliminary ruling binds the referring national court in resolving the dispute. It also provides an authoritative interpretation of EU law that other national courts must take into account when dealing with the same legal question.

The procedure is not designed to establish a separate European appeal system for every domestic case. Its purpose is to ensure that the same Union law is understood and applied consistently throughout the Member States.

The relationship is therefore one of judicial cooperation, although the authority of the CJEU’s interpretation is not optional. Once the Court has interpreted the relevant EU provision, the national court must decide the dispute in accordance with that interpretation.

This arrangement preserves a balance between centralised interpretation and decentralised adjudication: the CJEU safeguards the uniform meaning of EU law, while national courts remain responsible for deciding the proceedings before them.

7. Effective Judicial Protection and the Right to a Remedy

7.1. Article 19 TEU and Article 47 of the Charter

The practical enforcement of EU law requires more than substantive legal rights. Individuals must have access to judicial procedures capable of protecting those rights.

Article 19(1) TEU requires Member States to provide remedies sufficient to ensure effective legal protection in fields covered by Union law. Article 47 of the Charter of Fundamental Rights guarantees the right to an effective remedy and to a fair trial before an independent and impartial tribunal.

These provisions are closely connected. Article 19 TEU establishes an obligation concerning the judicial systems of Member States, while Article 47 protects individuals when they seek to enforce rights and freedoms guaranteed by EU law.

The principle does not require every Member State to adopt identical court structures or procedural codes. National judicial systems retain their institutional characteristics. However, their procedures must provide effective protection where EU law applies.

The CJEU has treated judicial independence as an essential element of this protection. A remedy is not genuinely effective if the court deciding the case is not sufficiently independent or impartial.

In Commission v Poland (Case C-204/21), concerning aspects of the Polish judicial disciplinary regime, the Court examined the relationship between judicial independence, effective judicial protection, and the obligations arising under Article 19 TEU. The judgment illustrates that the organisation of national courts may fall within the reach of EU law where those courts may be called upon to interpret and apply Union law. EUR-Lex+1

7.2. National procedural autonomy

In the absence of EU rules governing a particular procedural matter, it is generally for each Member State to establish the procedures through which rights derived from EU law are protected. This is known as national procedural autonomy.

It reflects the continuing importance of national legal systems. EU law does not establish a complete procedural code for every civil, administrative, criminal, or constitutional proceeding in the Member States.

However, procedural autonomy is subject to two fundamental requirements: equivalence and effectiveness.

The principle of equivalence requires that national rules governing claims based on EU law must not be less favourable than those governing comparable claims based on domestic law.

The principle of effectiveness requires that national procedural rules must not make the exercise of rights conferred by EU law impossible in practice or excessively difficult.

These principles were developed in early judgments such as Rewe-Zentralfinanz (Case 33/76) and have been refined through subsequent case law. They preserve a role for national procedural law while ensuring that domestic procedural arrangements do not undermine the effectiveness of Union rights. curia+1

For example, a Member State may establish limitation periods for claims seeking repayment of charges imposed contrary to EU law. Such periods are not automatically incompatible with EU law. Their length, starting point, practical operation, and relationship with comparable domestic claims must, however, satisfy the requirements of equivalence and effectiveness.

The same reasoning may apply to rules concerning evidence, jurisdiction, admissibility, remedies, and the enforcement of judgments.

7.3. The obligation to provide practical remedies

Effective judicial protection is not satisfied merely because a formal procedure exists. The remedy must be capable of addressing the legal injury in a meaningful way.

Depending on the relevant field and legal framework, effective protection may require:

• access to an independent and impartial court;
• the ability to challenge unlawful administrative action;
• appropriate interim measures where necessary;
• judicial review of decisions affecting rights under EU law;
• remedies capable of preventing or compensating for unlawful conduct;
• observance of fair-trial guarantees and reasonable procedural safeguards.

The precise remedy is not necessarily identical across Member States. The essential requirement is that national arrangements do not deprive EU rights of practical effectiveness.

This is one reason why the principles of primacy, direct effect, and effective judicial protection must be understood together. A directly effective right would be of limited value if no court could enforce it. Primacy would be weakened if procedural rules prevented a national judge from disapplying a conflicting rule. Effective judicial protection supplies the institutional and procedural conditions through which the substantive principles can operate.

8. The Limits of Primacy: Conferral, National Identity, and Constitutional Authority

8.1. Primacy operates within the competences conferred on the Union

The primacy of EU law is powerful, but it does not establish an unlimited European competence over national legal systems.

The principle of conferral, set out in Article 5 TEU, provides that the Union acts only within the limits of the competences conferred upon it by the Member States in the Treaties. Competences not conferred upon the Union remain with the Member States.

This is a fundamental constitutional boundary. The question whether a national rule conflicts with EU law can arise only where the relevant subject matter falls within the scope of Union law.

For example, a national measure may concern an area of domestic public administration in which the Union has no relevant competence and which is not otherwise connected to the implementation of EU law. In such a situation, the mere existence of the Union legal order does not automatically make the national measure subject to EU review.

The position changes where a national measure falls within the scope of a Treaty freedom, implements an EU directive, applies a regulation, or otherwise operates in a field governed by Union law.

The distinction is particularly important in relation to the Charter. Article 51(1) provides that the Charter binds Member States only when they are implementing Union law. The Charter does not create a general power for the EU institutions to regulate all domestic questions concerning fundamental rights, nor does it automatically apply to every national action.

The CJEU has interpreted the Charter’s scope broadly enough to cover situations in which national measures fall within the field of application of EU law, but it has not treated the Charter as a general instrument of constitutional supervision over national governments.

8.2. Article 4(2) TEU and respect for national identity

Article 4(2) TEU requires the Union to respect the equality of Member States and their national identities, inherent in their fundamental political and constitutional structures. It also recognises essential state functions, including territorial integrity, maintenance of law and order, and national security.

This provision is significant because the Union is not a federal state in which all constitutional authority has been transferred to a central government. Member States retain their own constitutional identities, institutions, and essential public responsibilities.

The provision nevertheless operates within the framework of the Treaties. It does not provide a general exemption from EU obligations whenever a national authority invokes constitutional identity.

The Court has considered national identity in several contexts, including citizenship, language, constitutional organisation, and the structure of public institutions. In Sayn-Wittgenstein (Case C-208/09), for example, the Court considered whether Austria could rely on its constitutional principle of abolishing noble titles to justify a restriction affecting the recognition of a name acquired in another Member State. The Court accepted that national identity could constitute a legitimate justification, subject to the requirements of EU law and proportionality.

The provision therefore calls for a legal assessment rather than an automatic priority rule. National constitutional identity must be taken seriously, but its invocation must be reconciled with the obligations arising from the Treaties.

8.3. Constitutional courts and the limits of European authority

The relationship between the CJEU and national constitutional courts has produced one of the most important constitutional debates in European law.

The CJEU maintains that EU law must enjoy primacy within its field of application, including in relation to national constitutional provisions. Its reasoning is that a Member State cannot unilaterally determine the legal effect of Union law through domestic constitutional rules without undermining the uniformity and effectiveness of the common legal order.

National constitutional courts, however, have sometimes expressed reservations about the extent of this claim. Their concerns have generally focused on questions such as:

• whether the Union has acted beyond the competences conferred upon it;
• whether EU institutions have respected fundamental constitutional principles;
• whether fundamental rights receive an adequate level of protection;
• whether the essential constitutional identity of the Member State is respected;
• whether European institutions and courts have remained within the limits of their legal authority.

The German Federal Constitutional Court’s jurisprudence provides an important example. In its Solange decisions, it examined the relationship between the protection of fundamental rights under German constitutional law and the developing Community legal order. The Court initially reserved the possibility of reviewing Community measures against German fundamental rights standards so long as the Community did not provide an adequate level of fundamental rights protection. It later accepted that, while the EU system maintained substantially equivalent protection, it would generally refrain from exercising such review.

The German court has also developed doctrines concerning constitutional identity and the limits of transferred powers. These positions illustrate that national constitutional courts do not always accept the CJEU’s account of primacy without qualification.

The constitutional debate is not confined to Germany. Other national constitutional courts have considered similar questions, sometimes producing tensions between domestic constitutional interpretations and the CJEU’s understanding of EU law.

The disagreement is structural. The CJEU views primacy as essential to the legal unity of the Union. National constitutional courts may regard themselves as having a continuing responsibility to ensure that constitutional powers are exercised within the limits authorised by their national constitutions.

The Treaties do not provide a simple hierarchy that eliminates every possible disagreement between these constitutional authorities. The preliminary ruling procedure, the principle of sincere cooperation, and the obligation to respect national identity are among the mechanisms through which such disputes may be addressed.

8.4. The Court of Justice’s position on constitutional resistance

The Court of Justice has consistently reaffirmed that Member States cannot rely on domestic law, including constitutional provisions, to undermine the effectiveness of EU law.

In RS (Case C-430/21), the Court considered the effects of decisions of a national constitutional court on the application of EU law by ordinary national courts. It reaffirmed that national courts must be able to give full effect to EU law and, where necessary, disapply national provisions that prevent them from doing so.

In Commission v Poland (Case C-448/23), the Court addressed the consequences of judgments of the Polish Constitutional Tribunal that challenged elements of the EU legal order and the binding authority of the CJEU’s case law. The Court reaffirmed the requirements of primacy, judicial independence, and effective judicial protection. It also considered the relationship between Article 4(2) TEU and the obligations arising from the rule of law and Article 19 TEU. EUR-Lex+1

The Court’s position is that national identity must be interpreted within the framework of the Treaties and cannot be used as a unilateral means of exempting a Member State from fundamental obligations arising from EU membership.

At the same time, Article 4(2) TEU remains part of primary EU law and must be given genuine legal consideration. The Court itself is required to interpret the Treaties as a whole, including the provision on national identity.

The constitutional relationship is therefore not simply a contest between European and national authority. It involves the interpretation of a shared legal framework in which both Union institutions and Member States have defined responsibilities.

8.5. Constitutional dialogue and institutional balance

The relationship between the CJEU and national constitutional courts is sometimes described as constitutional dialogue. The expression reflects the fact that constitutional disputes may be addressed through judicial references, reasoned judgments, treaty interpretation, and the development of common standards.

The term should not conceal the legal consequences of the dialogue. A preliminary ruling is binding on the referring court as regards the interpretation of EU law. National courts cannot treat an authoritative interpretation as merely advisory.

Nevertheless, the system depends on cooperation. National courts provide the factual and procedural context in which questions of EU law arise. They also identify conflicts between national rules and Union obligations. The CJEU, in turn, interprets EU law in a way that must be applied by national courts.

The principle of sincere cooperation under Article 4(3) TEU supports this relationship. Member States must take appropriate measures to fulfil Treaty obligations and refrain from measures that could jeopardise the achievement of Union objectives. The Union institutions, for their part, must respect the principle of conferral and the institutional structure established by the Treaties.

The system is thus based on mutual legal obligations, even though the CJEU has final authority to interpret EU law and determine the validity of Union acts.

9. How Primacy and Direct Effect Operate in Practice

The principles discussed above are easiest to understand when considered as parts of a single legal problem. A national court faced with an alleged conflict between domestic law and EU law must identify the relevant Union provision, establish whether it applies to the dispute, determine its legal effect, and select an appropriate remedy.

These questions should not be collapsed into one another. The fact that a rule of EU law has primacy does not automatically mean that an individual can invoke it directly. Equally, the absence of direct effect does not necessarily mean that the Member State has no obligation or that the individual has no possible remedy.

9.1. A structured approach to a conflict between national and EU law

A court dealing with a potential conflict may need to consider the following sequence.

First, does the dispute fall within the scope of EU law?

The court must identify the relevant Treaty provision, regulation, directive, decision, or other applicable source. It must also establish that the subject matter falls within the scope of Union law and that the Union has acted within its conferred competences.

A national measure does not become subject to EU law simply because it has some general connection with a European policy area. There must be a sufficient legal connection with a rule or field governed by the Treaties.

Second, what is the legal nature of the EU provision?

The court must determine whether the relevant rule is contained in primary law, a regulation, a directive, a decision, or another source. The legal instrument matters because Article 288 TFEU assigns different characteristics to different forms of Union legislation.

A regulation is directly applicable. A directive normally requires national transposition. A Treaty provision may be directly effective if it satisfies the relevant conditions. A decision may produce direct effects depending on its content and addressees.

Third, does the provision have direct effect?

The court must examine whether the particular provision is sufficiently clear, precise, and unconditional to be relied upon in judicial proceedings.

If the provision has direct effect, the court must consider whether it can be invoked against a public authority or, where the nature of the provision permits, against a private party.

Fourth, can the national rule be interpreted consistently with EU law?

Even where direct effect is unavailable, the court must consider whether domestic law can be interpreted in a way that achieves the result required by EU law. This is particularly important in disputes involving directives.

The interpretative obligation must, however, remain within the limits of national law and general principles such as legal certainty and non-retroactivity.

Fifth, if a genuine conflict remains, must the national rule be disapplied?

Where an applicable EU provision with the necessary legal effect conflicts with national law, the principle of primacy requires the national court to give effect to EU law. Under Simmenthal, the court must disapply the conflicting national provision to the extent necessary, without waiting for its formal repeal or constitutional annulment.

The precise consequences depend on the nature of the EU rule and the legal issue before the court. The principle does not authorise a court to disregard national legislation outside the scope of applicable EU law.

Sixth, is another remedy necessary?

If the state has breached EU law and the individual has suffered damage, state liability may provide a route to compensation. If the interpretation of EU law is uncertain, the national court may need to refer a question to the CJEU under Article 267 TFEU.

This sequence demonstrates that EU law operates through a combination of substantive rules, interpretative obligations, judicial cooperation, and remedies.

9.2. Example: An incorrectly implemented employment directive

Imagine that an EU directive requires Member States to guarantee a particular minimum employment protection. The deadline for transposition expires, but a Member State fails to adopt the necessary legislation.

An employee working for a public authority may be able to rely directly on a sufficiently clear and unconditional provision of the directive against that authority. The national court would need to determine whether the relevant provision satisfies the conditions for vertical direct effect and whether the defendant falls within the concept of the state.

If the employee works for a private company, the position is different. The directive cannot, by itself, ordinarily impose an obligation on the private employer. The court must consider whether existing national legislation can be interpreted consistently with the directive. If the state has failed to implement the directive and that failure has caused compensable loss, state liability may also become relevant.

The underlying EU obligation remains binding on the Member State in both situations. The difference concerns the legal route through which the individual may enforce the relevant right.

9.3. Example: A national statute conflicting with an EU regulation

Imagine that an EU regulation establishes a common rule governing a particular commercial transaction. A national statute adopted later introduces a requirement incompatible with that regulation.

Because regulations are directly applicable, the national court must determine whether the relevant provision of the regulation is capable of being applied to the dispute. If it is, and a genuine conflict exists, the later date of the national statute does not allow it to prevail.

The court must give effect to the applicable EU rule. It does not need to wait for the national legislature to amend the statute or for a constitutional court to declare it invalid.

This is the practical consequence of Costa v ENEL and Simmenthal: national legislation cannot unilaterally displace an applicable rule of Union law.

9.4. Example: A national procedural obstacle to an EU right

Imagine that a national procedural rule imposes a limitation period that makes it excessively difficult for consumers to recover charges unlawfully imposed under EU law.

The national court must examine whether the rule complies with the principles of equivalence and effectiveness. If the limitation period is less favourable than that governing comparable domestic claims, it may violate equivalence. If it makes the exercise of the EU right impossible in practice or excessively difficult, it may violate effectiveness.

The court must then consider the appropriate consequence under EU and national law.

The example illustrates that EU law does not regulate only the substantive content of national legislation. It can also influence the procedural arrangements through which national courts protect rights arising under Union law.

10. The Constitutional Significance of the EU Legal Order

The doctrines of primacy and direct effect are not isolated technical rules. Together, they explain why the EU legal order has a constitutional dimension.

The Union’s legal system is founded on treaties, but its operation cannot be reduced to conventional international cooperation. EU law may create rights for individuals, require national courts to disapply conflicting legislation, impose duties on public authorities, and establish judicial standards that national legal systems must respect.

This constitutional dimension is nevertheless qualified by the principle of conferral. The Union does not possess general authority over every matter governed by national law. Its institutions must act within the competences granted by the Treaties, and the Member States retain responsibility for matters not conferred upon the Union.

The resulting structure is neither a conventional international organisation nor a fully centralised federal state. It is a distinctive legal order in which Union authority and national constitutional systems operate in continuous interaction.

The Court of Justice has played a decisive role in developing this structure. Through Van Gend en Loos, Costa v ENEL, Simmenthal, Factortame, Francovich, and numerous subsequent judgments, it has established the principles that make Union law effective within national legal systems.

National courts are equally indispensable. They apply EU law in ordinary proceedings, protect rights derived from it, refer interpretative questions to the CJEU, and ensure that Union obligations are respected in practical situations.

The relationship remains constitutionally sensitive. National constitutional courts continue to examine the limits of transferred powers, the protection of fundamental rights, and the preservation of national constitutional identity. The Treaties recognise national identity, but they also establish obligations that cannot be set aside unilaterally by individual Member States.

The central feature of the system is therefore not the disappearance of national constitutional authority, but its operation within a legal order whose rules have binding consequences across all Member States. The challenge is to preserve the effectiveness and uniformity of Union law while respecting the constitutional framework that created the Union and continues to define its powers.

11. Key Takeaways

1. The EU legal order is founded on international treaties but has developed distinctive supranational characteristics that distinguish it from ordinary international organisations.

2. The principle of primacy means that applicable EU law takes precedence over conflicting national law within the scope of Union law.

3. In Costa v ENEL, the Court of Justice established that Member States cannot unilaterally override EU law through subsequent domestic legislation.

4. In Internationale Handelsgesellschaft, the Court confirmed that national constitutional rules cannot determine the validity or effect of EU law within the Union legal order.

5. Under Simmenthal, national courts must disapply conflicting national provisions immediately where necessary to give effect to applicable EU law. Formal repeal or constitutional annulment is not a prerequisite.

6. Direct effect allows individuals to rely on certain provisions of EU law before national courts where the relevant legal requirements are satisfied.

7. Direct applicability and direct effect are distinct concepts. Regulations are directly applicable, but the direct effect of a particular provision depends on its legal content.

8. Treaty provisions, regulations, and decisions may have direct effect where they are sufficiently clear, precise, and unconditional.

9. Directives may have vertical direct effect after the transposition deadline has expired if the relevant provision satisfies the necessary conditions and the claim is brought against the state or an entity treated as an emanation of the state.

10. Directives do not, as a general rule, have horizontal direct effect and cannot by themselves impose obligations on private parties.

11. The concept of an emanation of the state prevents Member States from avoiding directive obligations through certain forms of institutional delegation or public-service organisation.

12. The duty of consistent interpretation requires national courts to interpret domestic law, so far as possible, in the light of the wording and purpose of applicable EU directives.

13. State liability may entitle individuals to compensation for damage caused by sufficiently serious breaches of EU law attributable to a Member State.

14. Article 267 TFEU establishes the preliminary ruling procedure, enabling national courts to obtain authoritative interpretations of EU law from the CJEU.

15. Article 19 TEU and Article 47 of the Charter protect the requirement of effective judicial protection in fields governed by Union law.

16. National procedural autonomy remains important, but it is limited by the principles of equivalence and effectiveness.

17. Article 4(2) TEU requires the Union to respect national identities inherent in the fundamental political and constitutional structures of Member States.

18. The primacy of EU law operates within the competences conferred upon the Union and does not create a general European authority over all areas of national law.

12. Frequently Asked Questions

1. What is the EU legal order?

The EU legal order is the autonomous system of legal rules, principles, institutions, and judicial procedures established by the Treaties. It is based on international agreements between Member States but possesses distinctive supranational characteristics. Its rules can create rights and obligations that operate within national legal systems.

2. What is the principle of primacy of EU law?

Primacy means that where applicable EU law conflicts with national law, the EU rule must prevail within the scope of Union law. National authorities and courts cannot rely on domestic legislation to defeat the effectiveness of an applicable EU obligation.

3. Which case established the primacy of EU law?

The leading judgment is Costa v ENEL (Case 6/64), decided in 1964. The Court held that the legal system created by the European Community could not be overridden unilaterally by subsequent national legislation.

4. Does EU law prevail over national constitutions?

According to the CJEU’s established doctrine, EU law has primacy over conflicting national law, including constitutional provisions, within the scope of Union law. National constitutional courts have sometimes expressed reservations concerning the limits of conferred competences, fundamental rights, and national constitutional identity. These disagreements remain part of the constitutional debate surrounding European integration.

5. What is direct effect?

Direct effect means that a provision of EU law can be relied upon by individuals before national courts where it is sufficiently clear, precise, and unconditional. The doctrine was established in Van Gend en Loos (Case 26/62).

6. Are all EU laws directly effective?

No. Direct effect depends on the nature and content of the particular provision. A provision may require further legislative or administrative measures, leave substantial discretion to national authorities, or fail to establish an enforceable individual right.

7. What is the difference between direct effect and direct applicability?

Direct applicability means that an EU rule becomes applicable within Member States without national transposition. Direct effect means that a particular provision can be invoked before a court. Regulations are directly applicable, but the direct effect of individual provisions must still be assessed.

8. Do directives have direct effect?

Certain provisions of directives may have vertical direct effect after the implementation deadline has expired, provided they are sufficiently clear, precise, and unconditional and the Member State has failed to implement the directive correctly.

9. Can a directive be enforced against a private company?

As a general rule, an individual cannot rely on a directive itself to impose an obligation on a private company. This limitation follows from Marshall and Faccini Dori. However, national law may have to be interpreted consistently with the directive, and state liability may provide compensation where the conditions are satisfied.

10. What is vertical direct effect?

Vertical direct effect describes the ability of an individual to rely on an EU provision against the state or an entity treated as an emanation of the state. It is particularly important in relation to directives that have not been correctly implemented.

11. What is horizontal direct effect?

Horizontal direct effect means that an EU provision can be relied upon in a dispute between private parties. Certain Treaty provisions and other EU rules may have this effect, but directives do not, as a general rule, have horizontal direct effect.

12. What is the emanation of the state doctrine?

It is a doctrine used to determine whether an entity may be treated as part of the state for the purpose of enforcing EU obligations, particularly directives. The assessment considers the entity’s public responsibilities, relationship with public authorities, and any special powers it possesses.

13. What happens when national law conflicts with an EU regulation?

Where the relevant regulation applies and its provision is capable of being applied to the dispute, the national court must give effect to EU law. Under Simmenthal, it must disapply the conflicting national provision to the extent necessary, without waiting for formal repeal.

14. Can an individual claim compensation for a breach of EU law?

Yes, in certain circumstances. Under the state-liability doctrine developed in Francovich and Brasserie du Pêcheur, an individual may obtain compensation where the infringed EU rule was intended to confer rights, the breach was sufficiently serious, and a direct causal link exists between the breach and the damage.

15. What is the preliminary ruling procedure?

The preliminary ruling procedure under Article 267 TFEU allows national courts to ask the CJEU questions concerning the interpretation of EU law or the validity of Union acts. The CJEU answers the EU law question, while the national court resolves the underlying dispute.

16. Must national courts always refer questions to the CJEU?

No. National courts generally have discretion to refer questions where necessary. Courts of last instance are, in principle, required to refer relevant questions, subject to recognised exceptions, including where the question is irrelevant, has already been resolved, or the correct interpretation is beyond reasonable doubt under the CILFIT criteria.

17. Does the Charter of Fundamental Rights apply to every national decision?

No. Under Article 51 of the Charter, Member States are bound by it when they are implementing or otherwise acting within the scope of EU law. The Charter does not give the Union a general power to review every aspect of domestic law.

18. What is the relationship between primacy and national constitutional identity?

Primacy requires national authorities to give effect to applicable EU law, while Article 4(2) TEU requires the Union to respect national identities inherent in fundamental political and constitutional structures. The CJEU interprets national identity within the framework of the Treaties; it does not treat it as a general exemption from EU obligations.

19. Does EU law replace national law?

No. National legal systems continue to regulate extensive areas of public and private life. EU law applies within the competences and fields established by the Treaties. Where a genuine conflict arises within that scope, primacy determines which rule must be applied.

20. Why are national courts so important to the EU legal order?

National courts enforce EU law in ordinary disputes, protect rights conferred by Union law, apply the principles of primacy and direct effect, and cooperate with the CJEU through the preliminary ruling procedure. Without national courts, the practical effectiveness of EU law would be substantially reduced.

Conclusion

The relationship between EU law and national law is one of the defining features of the European Union’s constitutional development. The Treaties created a system of cooperation between states, but the Court of Justice’s jurisprudence established that this system could not function effectively if Union law depended entirely on the willingness of each Member State to apply it through its own domestic rules.

The doctrines of direct effect and primacy addressed two essential problems. Direct effect enabled individuals to rely on certain provisions of EU law before national courts. Primacy ensured that applicable Union rules could not be displaced by conflicting national legislation. The subsequent development of consistent interpretation, state liability, preliminary rulings, and effective judicial protection made these principles part of a broader system of legal enforcement.

Yet the Union remains a legal order based on conferred competences. Its authority is not unlimited, and the constitutional identity and essential functions of Member States remain recognised by the Treaties. The continuing dialogue between the CJEU and national constitutional courts reflects the complexity of a system in which European and national legal authority coexist.

The result is a distinctive constitutional arrangement: EU law is not merely an external obligation imposed on governments, but a body of law capable of operating within national legal systems, shaping the rights of individuals, and determining the obligations of public authorities. Its effectiveness depends on the combined operation of European institutions, national legislatures, administrative authorities, and domestic courts.

Principal Legal Sources and Further Reading

Treaties and primary legal texts

• Treaty on European Union (TEU) — particularly Articles 4, 5, 6, 19, and 47. EUR-Lex+1
• Treaty on the Functioning of the European Union (TFEU) — particularly Articles 267, 288, and 340. EUR-Lex
• Charter of Fundamental Rights of the European Union — particularly Articles 47 and 51.
• European Parliament: Sources and Scope of European Union Law — an overview of the hierarchy of EU law and the relationship between Union and domestic legal systems. European Parliament+1

Foundational judgments of the Court of Justice

• Van Gend en Loos, Case 26/62 — the recognition of direct effect and the distinctive nature of the Community legal order.
• Costa v ENEL, Case 6/64 — the establishment of the principle of primacy.
• Internationale Handelsgesellschaft, Case 11/70 — primacy in relation to national constitutional provisions.
• Simmenthal, Case 106/77 — the obligation of national courts to disapply conflicting national law.
• Factortame, Case C-213/89 — interim judicial protection and the effectiveness of EU rights.
• Van Duyn, Case 41/74 — direct effect of directives.
• Marshall, Case 152/84 — the absence of horizontal direct effect of directives.
• Faccini Dori, Case C-91/92 — confirmation of the limits of directive enforcement between private parties.
• Foster, Case C-188/89 and Farrell, Case C-413/15 — the concept of an emanation of the state.
• Von Colson, Case 14/83 and Marleasing, Case C-106/89 — consistent interpretation of national law.
• Francovich, Joined Cases C-6/90 and C-9/90 and Brasserie du Pêcheur and Factortame, Joined Cases C-46/93 and C-48/93 — state liability for breaches of EU law.
• Köbler, Case C-224/01 — state liability for sufficiently serious breaches attributable to national courts.
• Rewe, Case 33/76 — national procedural autonomy and the protection of EU rights.
• CILFIT, Case 283/81 — the obligation of courts of last instance to refer questions under Article 267 TFEU.

More recent judicial developments

• Commission v Poland, Case C-204/21 — judicial independence, effective judicial protection, and the obligations arising under Article 19 TEU. EUR-Lex
• RS, Case C-430/21 — the effects of national constitutional court decisions on the application of EU law.
• Commission v Poland, Case C-448/23 — primacy, national constitutional identity, and the binding authority of CJEU judgments. EUR-Lex+1
• KUBERA, Case C-144/23 — the obligation of courts of last instance to give reasons when deciding whether a preliminary reference is required. EUR-Lex