The Legal Nature of the European Union: A Supranational Legal Order Between International Law and Constitutionalism

The Legal Nature of the European Union: A Supranational Legal Order Between International Law and Constitutionalism

Introduction

The European Union occupies an unusual position in the architecture of modern international law. It is not a state, although it exercises public authority over individuals, businesses, national governments, and institutions within its legal order. It is not a conventional international organisation, although its existence and powers derive from treaties concluded by sovereign states. Nor is it simply a system of cooperation between national governments, because its legal rules can create rights for individuals, take precedence over conflicting national legislation, and be interpreted and enforced by an independent judicial institution.

The European Union is therefore best understood as a distinctive supranational legal order: a system of law established by international treaties but possessing institutional, judicial, and normative characteristics that go beyond traditional intergovernmental cooperation. Its authority is exercised within competences conferred by its Member States, yet the law adopted within those competences has consequences that penetrate national legal systems and directly affect legal relationships within them.

This legal character is one of the most significant innovations in modern constitutional and international law. The EU demonstrates that public authority need not be organised exclusively through the traditional model of the sovereign nation-state. States can establish a common legal framework, create institutions capable of exercising independent powers, and accept that certain rules adopted within that framework will bind not only governments but also individuals and national courts.

The resulting structure is neither entirely international nor entirely constitutional. Its foundations remain treaty-based, and the Member States continue to determine the limits of the Union’s powers. At the same time, the Treaties function as a constitutional framework for a legal order with its own institutions, principles, procedures, and mechanisms of judicial protection.

Understanding this dual character is essential to understanding almost every major area of EU law. It explains why EU legislation can have direct consequences for individuals, why national courts must sometimes disapply domestic legislation, why the Court of Justice of the European Union has a distinctive constitutional role, and why questions concerning sovereignty, democratic legitimacy, competence, and national constitutional identity remain central to European integration.

The legal nature of the EU is not merely a theoretical classification. It determines how the Union exercises authority, how its institutions interact with Member States, how conflicts between legal systems are resolved, and how the rights of individuals are protected.

1. The European Union as a Creation of International Treaties

The starting point for understanding the EU’s legal nature is its origin in agreements between sovereign states.

The European Communities and, subsequently, the European Union were established through international treaties. The founding states negotiated and ratified those agreements according to their respective constitutional procedures. The Treaties established common institutions, defined their powers, created procedures for adopting binding legal acts, and provided mechanisms for resolving disputes.

The current constitutional framework is principally contained in two treaties:

• The Treaty on European Union (TEU), which establishes the Union’s foundational values, objectives, institutional framework, and central constitutional principles.
• The Treaty on the Functioning of the European Union (TFEU), which specifies the Union’s competences, policies, institutional procedures, and substantive legal framework.

The Treaty establishing the European Atomic Energy Community (Euratom) remains a separate treaty framework, although Euratom shares institutions with the European Union.

These instruments are international agreements in their form and legal origin. They are concluded between states and governed by principles of international treaty law. Their amendment generally requires agreement between the Member States and ratification in accordance with their respective constitutional requirements, subject to the specific procedures established by the Treaties.

Article 48 TEU regulates the ordinary revision procedure and provides for simplified revision procedures in certain circumstances. The Member States therefore remain the ultimate authors of the Union’s foundational treaty framework.

However, the international origin of the Treaties does not fully explain the legal system they created.

In a conventional international organisation, member states generally undertake obligations towards one another. The organisation may adopt decisions or recommendations, but its authority over individuals is often indirect and dependent on national implementation. Its institutional powers are ordinarily limited by the principle that states retain control over the organisation’s activities.

The European Union differs in several fundamental respects.

First, EU institutions may adopt legally binding acts within the competences conferred upon them. Depending on the legal instrument, those acts may apply directly within Member States without requiring national legislation.

Second, individuals and companies may derive enforceable rights from EU law. These rights are not merely political benefits granted by national governments; they may be invoked before national courts under the conditions established by EU law.

Third, the Court of Justice of the European Union exercises independent judicial authority. It interprets the Treaties, reviews the legality of EU institutional action, and ensures the uniform interpretation of EU law throughout the Union.

Fourth, national courts form part of the practical system through which EU law is applied and enforced. They are not simply external authorities implementing international obligations. They are required to protect rights arising under EU law and to cooperate with the Court of Justice through the preliminary ruling procedure.

The Union thus possesses a legal structure that cannot be adequately described as an ordinary treaty-based organisation.

The treaties establish the Union, but the legal order created by those treaties has developed characteristics of its own.

2. The Concept of a Supranational Legal Order

The term supranational describes an institutional and legal structure in which states establish common authorities capable of exercising powers independently of individual national governments within defined areas of competence.

Supranationalism differs from ordinary intergovernmental cooperation.

In an intergovernmental system, governments remain the principal decision-makers. Decisions are generally taken through agreement between states, and the implementation of common policies often depends upon national action. Each state retains substantial control over the legal consequences of cooperation.

A supranational system introduces a different arrangement. States agree in advance to establish institutions that can exercise common powers according to procedures laid down in the founding treaties. In certain areas, decisions may be adopted by qualified majority rather than unanimous agreement. Once validly adopted, those decisions may bind all Member States, including governments that opposed them during the legislative process.

The EU combines supranational and intergovernmental elements.

The European Commission generally acts in the common interest of the Union rather than as a representative of individual national governments. The European Parliament represents EU citizens directly and participates in legislation and budgetary decisions. The Court of Justice interprets EU law independently. The Council of the European Union represents Member State governments, while the European Council provides political direction and consists of the heads of state or government.

The institutional system is therefore not based on a simple hierarchy of national governments.

It is a system of divided institutional authority in which different bodies represent different sources of political and legal legitimacy.

The supranational character of the EU is particularly visible in three areas.

First, the autonomy of EU institutions. The institutions exercise powers conferred upon them by the Treaties and must act within the limits of those powers. They are not merely agents carrying out instructions from individual national governments.

Second, the binding force of EU law. EU regulations, directives, decisions, and other legally relevant instruments may create obligations and rights that operate within national legal systems.

Third, judicial enforcement. The Court of Justice and national courts cooperate to maintain the effectiveness, consistency, and uniform interpretation of the Union’s legal order.

Supranationalism does not mean that the EU possesses unlimited authority over its Member States. The Union is governed by the principle of conferral, and its powers remain limited to those granted by the Treaties.

The distinction is important. The EU is supranational because it exercises certain common powers through independent institutions and a legal order with effects within Member States. It is not sovereign in the same manner as a state.

Its authority is both autonomous in its operation and limited in its constitutional foundation.

3. The European Union Is Not a State

The EU has several characteristics commonly associated with states. It has a defined territorial scope through the territories of its Member States, a permanent population affected by its legal acts, institutions exercising public authority, a legal system, a budget, and the capacity to conclude international agreements.

It also possesses legal personality under Article 47 TEU.

Nevertheless, these characteristics do not make the Union a state.

A state ordinarily possesses general public authority over its territory and population, subject to its constitutional arrangements and international obligations. Its legal order is generally capable of regulating a broad range of public and private matters. It has its own constitutional system, political institutions, and ultimate authority over the organisation of government within its jurisdiction.

The EU does not possess general competence.

Article 5 TEU establishes that the limits of Union competences are governed by the principle of conferral. The Union may act only within the limits of the competences conferred upon it by the Member States in the Treaties to attain the objectives set out therein. Competences not conferred upon the Union remain with the Member States.

This means that the EU cannot simply legislate in any field because a common policy would be politically desirable or economically useful.

Its authority must have a legal basis in the Treaties.

The Member States retain responsibility for numerous fundamental areas of public administration and national constitutional organisation. They maintain their own constitutions, governments, parliaments, judicial systems, taxation systems, and public authorities. They also retain important powers in fields such as national security and the organisation of their armed forces, subject to applicable EU and international obligations.

The Union does not possess a general power to impose a uniform constitutional structure upon its Member States. It does, however, require them to respect the values set out in Article 2 TEU, including human dignity, freedom, democracy, equality, the rule of law, and human rights.

Nor does the EU possess an independent general power of taxation comparable to that of a state. Its budget is financed through the system of own resources and other revenues established under the Treaties and applicable decisions.

The distinction between the Union and a state is also reflected in the legal status of EU citizenship.

Article 20 TFEU establishes citizenship of the Union for every person holding the nationality of a Member State. EU citizenship supplements national citizenship; it does not replace it. The Union does not independently determine the nationality of its citizens.

The EU is therefore not a state in the conventional constitutional sense. It is a treaty-based political and legal union whose authority depends upon the competences conferred by its Member States.

This distinction is essential because it prevents the concept of supranationalism from being confused with the creation of a European sovereign state.

4. The European Union Is More Than a Conventional International Organisation

Although the EU is not a state, it differs considerably from traditional international organisations.

Organisations such as the United Nations, the World Trade Organization, and the Council of Europe are also established through international agreements. They possess institutional structures and legal personalities and can adopt decisions within their respective mandates.

However, the EU’s legal order has developed a particularly strong relationship with the domestic legal systems of its Member States.

The most important difference is that EU law can operate directly within national legal systems and may require national courts to give it priority over conflicting domestic legislation.

This is not a general feature of international law.

Under traditional international law, treaties ordinarily create obligations for states. Whether individuals may invoke those treaties before domestic courts depends upon the constitutional arrangements of each state and the legal character of the relevant provision.

The EU legal order developed a different approach.

Certain provisions of EU law can confer rights upon individuals that national courts must protect. Some EU acts apply without national transposition. Other acts require national implementation but may still produce legal consequences when a Member State fails to comply with its obligations.

Furthermore, the Court of Justice has developed doctrines designed to ensure that EU law is applied effectively and uniformly across the Union.

The legal consequences of these doctrines are profound.

A national legislature cannot necessarily preserve the effect of a domestic law simply by adopting it after an EU obligation has arisen. A national court may be required to disapply a conflicting national rule in a case before it. A Member State may incur liability where a sufficiently serious breach of EU law causes loss to individuals.

These features distinguish the EU from an organisation whose legal acts remain dependent upon the political willingness of each government to implement them.

The Union’s legal system is therefore unusual: it is founded upon international treaties but operates through institutions and judicial mechanisms that create a legal relationship between the Union, its Member States, and individuals.

5. The Foundational Jurisprudence: A New Legal Order

The constitutional character of EU law was not fully apparent from the wording of the original founding treaties. It emerged through the interpretation of those treaties by the Court of Justice, particularly during the 1960s.

Two judgments are especially important: Van Gend en Loos and Costa v ENEL.

Together, they established the foundations of direct effect and primacy, two doctrines central to the autonomy and effectiveness of the EU legal order.

5.1 Van Gend en Loos: The Creation of a New Legal Order

In Case 26/62, Van Gend en Loos v Nederlandse Administratie der Belastingen (1963), the Court of Justice considered whether an individual company could rely upon a provision of the EEC Treaty before a national court.

The dispute concerned customs duties imposed by the Netherlands on the importation of a chemical product from Germany. The company argued that the increase in the duty violated Article 12 of the EEC Treaty, which prohibited Member States from introducing new customs duties or increasing existing ones between themselves.

The central question was whether that treaty provision created rights that individuals could enforce before national courts.

The Dutch government and several other governments argued that the Treaty was an agreement between states and that its obligations were primarily matters for interstate enforcement.

The Court rejected that interpretation.

It held that the European Economic Community constituted a new legal order of international law for the benefit of which the states had limited their sovereign rights, albeit within limited fields, and whose subjects included not only Member States but also their nationals.

The Court reasoned that the Treaty had objectives extending beyond the creation of reciprocal obligations between governments. Its preamble and institutional structure demonstrated that the Community was intended to affect individuals directly.

The Court therefore recognised that certain provisions of Community law could have direct effect.

A provision could be relied upon by individuals before national courts where it was sufficiently clear, precise, and unconditional, and did not depend upon further implementing measures.

The importance of the judgment cannot be overstated.

It established that individuals were not merely beneficiaries of interstate cooperation. They could become subjects of the Community legal order, possessing rights enforceable through national judicial systems.

The judgment also introduced a distinctive understanding of the relationship between international treaties and domestic legal systems.

The Community was no longer viewed solely as an agreement regulating relations between governments. It was recognised as a legal system capable of creating rights for individuals.

5.2 Costa v ENEL: The Primacy of Community Law

The second foundational judgment was Case 6/64, Flaminio Costa v ENEL (1964).

The case concerned Italian legislation nationalising the electricity sector and establishing the national electricity undertaking ENEL. Mr Costa, a shareholder in a private electricity company, challenged the national legislation and argued that it conflicted with obligations arising under the EEC Treaty.

The Court of Justice had to consider whether a Member State could rely upon a later national law to defeat obligations arising from Community law.

It held that the EEC Treaty had created its own legal system, integrated into the legal systems of the Member States, which their courts were bound to apply.

The Court reasoned that the Member States had established a Community of unlimited duration, possessing its own institutions, legal personality, capacity, and powers arising from limitations of sovereignty or transfers of powers from the states to the Community.

The Member States could not therefore allow subsequent domestic legislation to prevail over the legal order they had accepted on a reciprocal basis.

The judgment established the principle of primacy, also known as supremacy, of Community law.

Under this principle, where a valid and applicable rule of EU law conflicts with national law, EU law must prevail within the scope of Union competence.

The principle protects the uniformity and effectiveness of the Union’s legal order. Without it, each Member State could determine independently whether and how to apply EU obligations, undermining the common legal framework.

The Court’s reasoning was constitutional in its consequences, even though the legal system remained founded upon international treaties.

5.3 Internationale Handelsgesellschaft: Primacy and Fundamental Rights

The development of primacy raised an important constitutional question: what happens when EU law conflicts with fundamental rights protected by a national constitution?

In Case 11/70, Internationale Handelsgesellschaft (1970), the Court of Justice held that the validity of Community measures could not be affected by allegations that they conflicted with national constitutional rules or fundamental rights.

The Court reasoned that the validity and effects of Community law had to be assessed by reference to Community law itself. Allowing national constitutional standards to determine the validity of Community acts would undermine the uniformity and effectiveness of the common legal order.

However, the Court also recognised that fundamental rights formed part of the general principles of Community law and that their protection was inspired by the constitutional traditions common to the Member States.

This judgment illustrates the distinctive constitutional development of the EU.

The Court asserted the autonomy and primacy of Community law while simultaneously developing a framework for protecting fundamental rights within that legal order.

The later adoption of the EU Charter of Fundamental Rights and its binding legal status under Article 6 TEU further strengthened this dimension.

5.4 Simmenthal: The Duty of National Courts

The practical consequences of primacy were clarified in Case 106/77, Amministrazione delle Finanze dello Stato v Simmenthal (1978).

The Court held that national courts must give full effect to EU law and must, where necessary, refuse to apply conflicting national legislation.

This obligation applies even where the national legislation was adopted after the relevant EU rule.

National courts must not wait for the legislature to repeal the conflicting law or for a constitutional court to declare it invalid before protecting rights arising under EU law.

The national court must ensure that EU law is effective in the case before it.

This judgment is central to the practical operation of the EU legal order. It transforms primacy from an abstract principle into a judicial obligation operating throughout the Member States.

The national courts become essential participants in the enforcement of EU law.

6. The Autonomy of the EU Legal Order

Direct effect and primacy explain how EU law operates within national legal systems. A further principle explains why the Union’s legal order must be understood as an autonomous system: the doctrine of autonomy.

Autonomy means that EU law has its own sources, institutions, interpretative principles, and procedures for determining its meaning and validity. Its legal authority cannot be reduced to the domestic law of individual Member States or to the ordinary rules governing relations between states.

The principle is closely connected to the Court of Justice’s responsibility to ensure that EU law is interpreted and applied uniformly.

If every Member State could determine independently what an EU provision meant, the same regulation or treaty provision might produce different legal consequences in different countries. The internal market, common policies, and common rights would become fragmented.

Autonomy therefore protects the coherence of the Union’s legal system.

6.1 The Treaties as the Constitutional Charter of the Union

In Case 294/83, Parti écologiste “Les Verts” v European Parliament (1986), the Court of Justice described the European Economic Community as a Community based on the rule of law. It emphasised that neither the Member States nor the institutions could avoid review of whether their acts complied with the Treaties.

The Court referred to the Treaty as a constitutional charter, notwithstanding its origin in an international agreement.

This description captures the constitutional dimension of EU law. The Treaties do more than establish reciprocal obligations between governments. They organise public authority, distribute powers, establish institutions, define legislative procedures, protect legal rights, and provide judicial remedies.

The constitutional analogy is significant but must be used carefully. The EU Treaties are not a constitution adopted by a European sovereign people in the same manner as the constitution of a state. They remain international agreements concluded and revised by the Member States. Their constitutional function arises from the legal and institutional system they establish.

The Treaties therefore occupy a position comparable to constitutional instruments within the Union’s legal order, while retaining their international-law foundation.

6.2 Autonomy and the Uniform Interpretation of EU Law

The autonomy of EU law requires that its meaning be determined through the legal system established by the Treaties.

The Court of Justice is the authoritative interpreter of EU law. National courts may interpret and apply EU rules in individual cases, but they must operate within the framework of interpretation established by the Court.

Article 267 TFEU provides the preliminary ruling procedure through which national courts may refer questions concerning the interpretation of the Treaties or the validity and interpretation 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 Court of Justice does not ordinarily decide the underlying national dispute. Instead, it provides an authoritative interpretation of EU law or determines the validity of the relevant EU act, after which the national court resolves the case.

This arrangement creates a judicial dialogue between national courts and the Court of Justice. It also allows EU law to develop through the practical experience of litigation throughout the Member States.

Autonomy does not eliminate national judicial authority. Rather, it establishes a common interpretative framework within which national courts perform their functions.

6.3 Autonomy in Relations with International Law

The EU is itself an actor in international law. It may conclude international agreements, participate in international organisations where the Treaties permit, and undertake obligations towards third countries and international institutions.

However, international agreements concluded by the Union must respect the constitutional structure and fundamental principles of EU law.

In Opinion 2/13, concerning the proposed accession of the EU to the European Convention on Human Rights, the Court of Justice found that the draft accession agreement was incompatible with EU law as it then stood. The Court’s concerns included the autonomy of the EU legal order, the specific characteristics of EU law, and the allocation of judicial responsibilities under the Treaties.

The opinion did not mean that the Union could never accede to the Convention. It meant that the proposed agreement, in the form examined by the Court, did not adequately preserve the constitutional requirements of the EU legal system.

The issue illustrates an important distinction: the EU is subject to international law, but the interpretation and operation of its own legal order cannot be surrendered in a manner inconsistent with the Treaties.

Autonomy is therefore not a claim that EU law exists outside international law. It is a claim that the Union’s internal legal system has a distinct constitutional structure that must be preserved when it interacts with external legal regimes.

7. The Principle of Conferral and the Limits of Supranational Authority

The supranational character of the EU must be understood alongside the limits placed upon its powers.

Unlike a state with general legislative competence, the Union may act only within the competences conferred upon it by the Member States through the Treaties.

Article 5 TEU identifies three central principles governing the exercise of Union powers:

1. The principle of conferral.
2. The principle of subsidiarity.
3. The principle of proportionality.

These principles form part of the constitutional balance between the Union and its Member States.

7.1 Conferral: The Union Has Only the Powers Granted to It

Under Article 5(2) TEU, 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 principle establishes the legal foundation of the Union’s authority.

Every EU legislative act must have an appropriate legal basis in the Treaties. The choice of legal basis is not merely a technical question. It determines the objectives of the measure, the extent of the Union’s authority, and sometimes the legislative procedure and institutional participation required for its adoption.

For example, Article 114 TFEU permits the adoption of measures approximating national laws where their purpose is the establishment and functioning of the internal market. It does not confer a general power to harmonise all areas of national law simply because differences between national systems exist.

The Court of Justice may review whether an EU measure has been adopted on a valid legal basis. An institution cannot expand its powers merely by asserting that a particular policy would advance European integration.

The principle of conferral therefore distinguishes the EU from a federal state possessing a general constitutional allocation of legislative authority. The Union’s competences are derived from the Treaties, and their limits remain legally significant.

7.2 Exclusive, Shared, and Supporting Competences

Articles 2–6 TFEU classify the principal categories of Union competence.

Exclusive competence exists where only the Union may legislate and adopt legally binding acts, while Member States may do so only if empowered by the Union or for the implementation of Union acts.

Examples include the customs union, the establishment of competition rules necessary for the functioning of the internal market, monetary policy for Member States whose currency is the euro, the conservation of marine biological resources under the common fisheries policy, and the common commercial policy.

Shared competence exists where both the Union and Member States may legislate and adopt legally binding acts. Member States exercise their competence to the extent that the Union has not exercised its own, or where the Union has decided to cease exercising it.

Examples include the internal market, certain aspects of social policy, economic, social and territorial cohesion, agriculture and fisheries (subject to the specific exclusion concerning marine biological resources), environment, consumer protection, transport, energy, and the area of freedom, security and justice.

Supporting, coordinating, or supplementing competence allows the Union to support or coordinate Member State action without replacing national competence in the relevant field.

Examples include education, culture, tourism, civil protection, and certain aspects of public health.

The classification matters because it determines the extent to which the Union may adopt binding legislation and the extent to which national authorities retain independent legislative authority.

7.3 Subsidiarity: Decisions Should Be Taken at the Appropriate Level

The principle of subsidiarity applies in areas that do not fall within the Union’s exclusive competence.

Under Article 5(3) TEU, the Union should act only where the objectives of the proposed action cannot be sufficiently achieved by the Member States, either at central level or at regional and local level, but can rather, by reason of the scale or effects of the proposed action, be better achieved at Union level.

Subsidiarity is therefore concerned with the appropriate level of decision-making.

It recognises that not every policy problem requires a European legislative response. Where national, regional, or local authorities can achieve an objective sufficiently, Union intervention may be unnecessary.

However, where the problem crosses national borders or requires common standards to prevent fragmentation, action at Union level may be justified.

The principle is supported by Protocol No 2 on the Application of the Principles of Subsidiarity and Proportionality. It gives national parliaments a role in reviewing draft legislative acts and raising concerns where they consider that the subsidiarity principle has not been respected.

Subsidiarity is not a general political veto exercised by individual Member States. It is a legal and institutional principle intended to ensure that Union action is justified by the nature and scale of the matter being regulated.

7.4 Proportionality: Union Action Must Not Exceed What Is Necessary

The principle of proportionality, set out in Article 5(4) TEU, requires that the content and form of Union action do not exceed what is necessary to achieve the objectives of the Treaties.

A measure may pursue a legitimate EU objective and still be unlawful if it imposes requirements that are excessive in relation to that objective.

Proportionality is relevant to legislative design, administrative action, sanctions, restrictions on rights, and judicial review.

It requires institutions to consider whether a measure is suitable for achieving its objective, whether a less restrictive measure could achieve that objective, and whether the burdens imposed are excessive in relation to the benefits pursued.

Together, conferral, subsidiarity, and proportionality establish that supranational authority is legally structured rather than unlimited.

8. The Constitutional Relationship Between EU Law and National Law

The relationship between EU law and national law is one of the defining features of the Union’s legal nature.

EU law is not simply an external set of obligations that national governments may choose to implement in whatever manner they consider appropriate. Within the scope of Union competence, it forms part of the legal environment in which national public authorities, courts, businesses, and individuals operate.

Nevertheless, the relationship is not organised through a universally agreed federal hierarchy. It is shaped by EU law, national constitutional law, and the continuing interaction between the Court of Justice and national constitutional courts.

8.1 Primacy as a Requirement of Uniformity

The Court of Justice regards primacy as necessary to preserve the effectiveness and uniform application of EU law.

If a Member State could refuse to apply EU law whenever its national legislature adopted a conflicting statute, the common legal order would become dependent upon the political choices of individual governments.

The Court’s approach requires national courts to give effect to applicable EU law and, where necessary, disapply conflicting national rules.

Importantly, primacy does not mean that EU law automatically invalidates or repeals the national legislation concerned. The national rule may remain formally part of the domestic legal system. The consequence is that it cannot be applied in the particular situation where it conflicts with a rule of EU law that must prevail.

The Lisbon Treaty did not insert a general primacy article into the main body of the Treaties. However, Declaration No 17 concerning primacy, annexed to the Final Act of the Lisbon Intergovernmental Conference, recalls the established case law of the Court of Justice and confirms that the Treaties and law adopted on their basis have primacy over Member State law under the conditions established by that case law. EUR-Lex+1

8.2 The Position of National Constitutional Courts

National constitutional courts have not always accepted the Court of Justice’s understanding of primacy without qualification.

Several constitutional courts have developed doctrines concerning the limits of European integration and the protection of national constitutional structures.

The German Federal Constitutional Court, for example, has developed jurisprudence concerning constitutional identity and the limits of the authority transferred to the EU. Other national constitutional courts have expressed concerns about fundamental rights protection, democratic legitimacy, the division of competences, and the preservation of essential constitutional principles.

These positions reflect a deeper constitutional question: does the authority of EU law derive exclusively from the autonomous legal order established by the Treaties, or does its domestic effect ultimately depend upon the constitutional authorisation given by each Member State?

The Court of Justice emphasises the autonomy and primacy of EU law. National constitutional courts often emphasise the continuing authority of national constitutions as the foundation for participation in European integration.

The relationship is therefore not always free from tension.

In practice, many conflicts are resolved through judicial dialogue, preliminary references, and attempts to interpret national and EU law consistently. However, disagreements remain possible, particularly where a national court considers that an EU institution has exceeded its competences or that a measure threatens a fundamental constitutional principle.

8.3 National Identity Under Article 4(2) TEU

Article 4(2) TEU requires the Union to respect the equality of Member States before the Treaties and their national identities, inherent in their fundamental political and constitutional structures, including regional and local self-government.

This provision recognises that European integration does not require the disappearance of national constitutional diversity.

Member States retain different constitutional traditions, institutional arrangements, languages, and systems of public administration. The EU legal order must operate while respecting the constitutional and political structures protected by the Treaties.

However, Article 4(2) is not a general authorisation for Member States to disregard EU law whenever a national authority invokes constitutional identity.

The Court of Justice has emphasised that the concept must be interpreted within the structure and objectives of EU law and in accordance with the principle of sincere cooperation under Article 4(3) TEU. National identity must also be understood consistently with the fundamental values of the Union.

In Case C-430/21, RS (2022), the Court considered the relationship between national constitutional arrangements, judicial independence, and the effectiveness of EU law. Its reasoning reinforced that Article 4(2) TEU cannot be treated as a unilateral power allowing national authorities to disapply EU law outside the framework of the Treaties.

The provision therefore performs a balancing function. It protects constitutional diversity while preserving the unity and effectiveness of the Union’s legal order. Cour de justice de l’Union européenne+1

8.4 The Principle of Sincere Cooperation

Article 4(3) TEU requires the Union and the Member States to assist each other in carrying out tasks arising from the Treaties.

Member States must take appropriate measures to fulfil their obligations under EU law, facilitate the achievement of Union objectives, and refrain from measures that could jeopardise those objectives.

This principle, commonly called sincere cooperation, is central to the practical operation of the EU legal order.

It applies to national legislatures, administrative authorities, and courts. It requires governments to implement EU obligations in good faith and to cooperate with Union institutions in the enforcement of common rules.

The principle also operates in the other direction: Union institutions must respect the obligations and competences of Member States under the Treaties.

Sincere cooperation is therefore not simply a duty of national obedience. It is a structural principle governing the relationship between the Union and its Member States.

9. The Institutional Structure: A Legal Order Without a Single Sovereign Government

The institutional design of the EU reflects its hybrid nature.

Unlike a conventional international organisation, the Union does not depend exclusively upon representatives of national governments. Unlike a state, it does not possess a single sovereign legislature or executive exercising general public authority.

Instead, its institutional framework distributes powers among bodies representing different interests and sources of legitimacy.

Article 13 TEU identifies the Union’s institutions:

• The European Parliament.
• The European Council.
• The Council of the European Union.
• The European Commission.
• The Court of Justice of the European Union.
• The European Central Bank.
• The Court of Auditors.

Each institution acts within the limits of the powers conferred upon it by the Treaties and in accordance with the procedures, conditions, and objectives laid down in them.

9.1 The European Commission

The Commission promotes the general interest of the Union and takes appropriate initiatives to that end. It ordinarily has the power to propose EU legislation, supervises the application of EU law under the Treaties, and performs executive and administrative functions.

Its members are required to act independently and must not seek or take instructions from national governments or other institutions.

The Commission’s independence is a defining supranational feature. It is designed to prevent the Union’s executive functions from becoming merely an extension of national government policy.

9.2 The European Parliament

The European Parliament represents EU citizens directly.

It participates in the adoption of legislation, exercises budgetary authority jointly with the Council, and scrutinises the work of other institutions, particularly the Commission.

Its directly elected composition provides a democratic dimension to the Union’s institutional structure.

However, Parliament does not possess the same general legislative authority as a national parliament. Its powers are defined by the Treaties and are exercised within the institutional procedures established there.

9.3 The Council of the European Union

The Council represents the governments of the Member States. It consists of a representative of each Member State at ministerial level, authorised to commit the government of that state and cast its vote.

Together with the European Parliament, the Council exercises legislative and budgetary functions.

Its participation ensures that national governments remain directly involved in the development of Union policy.

9.4 The European Council

The European Council consists of the heads of state or government of the Member States, together with its President and the President of the Commission. It defines the general political directions and priorities of the Union.

It does not ordinarily exercise legislative functions.

Its role demonstrates the continuing importance of intergovernmental political leadership within the EU’s supranational framework.

9.5 The Court of Justice of the European Union

The Court of Justice ensures that the law is observed in the interpretation and application of the Treaties.

It reviews the legality of acts adopted by EU institutions, interprets EU law through preliminary rulings, and hears certain disputes involving Member States and EU institutions.

Its independence is essential to the autonomy of the Union’s legal order.

The Court’s authority is not based upon direct political control by national governments. It derives from the judicial powers conferred by the Treaties and the obligation of Member States and EU institutions to respect its jurisdiction.

The institutional structure is therefore a system of divided authority. It combines supranational independence, national governmental representation, and direct democratic participation.

10. The Sources of EU Law and Its Internal Legal Hierarchy

A legal order requires identifiable sources of law and rules governing their relationship.

EU law has developed a hierarchy of legal sources that reflects the constitutional structure of the Union.

10.1 Primary Law

Primary law occupies the highest position within the ordinary hierarchy of EU law.

Its principal sources include:

• The Treaty on European Union.
• The Treaty on the Functioning of the European Union.
• The Euratom Treaty, within its separate legal framework.
• Protocols and annexes attached to the Treaties.
• The Charter of Fundamental Rights of the European Union.
• General principles of EU law developed through the case law of the Court of Justice.

The TEU and TFEU have equal legal value under Article 1 TEU. They establish the Union’s institutional structure, objectives, competences, procedures, and fundamental principles.

The Charter of Fundamental Rights has the same legal value as the Treaties under Article 6(1) TEU. It binds EU institutions and applies to Member States when they are implementing or otherwise acting within the scope of EU law. It does not extend the competences of the Union.

General principles of EU law also play an important role. These include legal certainty, proportionality, legitimate expectations, equality, effective judicial protection, and respect for fundamental rights.

10.2 Secondary Law

Secondary law consists of legal acts adopted by EU institutions under the authority of the Treaties.

Article 288 TFEU identifies five principal categories:

Regulations have general application, are binding in their entirety, and are directly applicable in all Member States.

Directives are binding as to the result to be achieved but leave national authorities the choice of form and methods. They ordinarily require transposition into national law.

Decisions are binding in their entirety. Where they specify addressees, they are binding only upon those addressees.

Recommendations and opinions have no binding force.

The distinction between direct applicability and direct effect is important. A regulation does not require national transposition, but whether a particular provision can be invoked directly before a court depends upon its content and legal characteristics. Similarly, directives ordinarily require implementation, and their provisions may have vertical direct effect under established conditions when the Member State has failed to implement them correctly or on time. They do not, as a general rule, have horizontal direct effect in disputes solely between private parties.

10.3 International Agreements Concluded by the Union

The EU may conclude international agreements within the scope of its external competences.

Under Article 216(2) TFEU, agreements concluded by the Union are binding upon its institutions and Member States.

Such agreements form part of the EU legal order, although their relationship with primary law and secondary legislation is governed by the Treaties and the case law of the Court of Justice.

An EU institution cannot validly adopt an act that conflicts with the Treaties. Secondary legislation must therefore comply with primary law, including the Charter and general principles applicable to the relevant matter.

10.4 The Role of Case Law

The judgments of the Court of Justice are indispensable to understanding EU law.

The Court interprets treaty provisions, clarifies the legal effects of legislative acts, develops general principles, and ensures that EU law is applied consistently.

Its case law has played a particularly important role in the development of direct effect, primacy, state liability, fundamental rights protection, and the autonomy of the Union legal order.

EU law is therefore not simply a collection of written legislative instruments. It is a developed legal system in which judicial interpretation has played a formative constitutional role. European Parliament+2

11. The Union’s Legal Personality and Its Capacity to Act Internationally

An important distinction must be drawn between the legal personality of the European Union and the legal personality of its Member States.

Before the Lisbon Treaty entered into force, the European Union’s institutional and legal structure was more fragmented. The European Communities possessed legal personality, while the Union itself operated through the institutional framework established by the Maastricht Treaty without an express provision granting it a single legal personality.

The Lisbon Treaty changed this arrangement.

Article 47 TEU now provides expressly that the Union has legal personality. This means that the EU can act as a legal person in its own right, independently of the separate legal personalities of its Member States.

Legal personality gives the Union the capacity to exercise rights and assume obligations under international and domestic law within the limits of its competences.

It enables the Union to:

• Conclude international agreements.
• Participate in international organisations where the relevant legal framework permits.
• Establish diplomatic relations and maintain external representation.
• Acquire, own, and dispose of property.
• Enter into contracts.
• Bring legal proceedings and be subject to legal proceedings.
• Assume international responsibilities within the scope of its activities.

The Union’s international legal personality is particularly significant in external relations. It allows the EU to negotiate and conclude agreements with third countries and international organisations in areas where it has competence.

For example, the common commercial policy is an area of exclusive Union competence under Article 3 TFEU. The Union therefore acts as the principal legal and negotiating entity in the development of common commercial agreements falling within that policy.

However, legal personality must not be confused with sovereignty.

International organisations may possess legal personality without being states. Their capacity to act is defined by their constituent instruments and the powers necessary to perform their functions.

The same principle applies to the EU. Article 47 TEU gives the Union legal personality, but it does not grant it general competence over every matter affecting its Member States.

The Union’s international activity remains governed by the principle of conferral, the division of competences between the Union and its Member States, and the procedural requirements of the Treaties.

The EU is therefore an international legal person with a distinctive supranational legal order, rather than a sovereign state with unlimited external authority.

12. Fundamental Rights and the Constitutional Character of EU Law

The protection of fundamental rights is another major element of the EU’s constitutional development.

The original European Community Treaties did not contain a comprehensive written catalogue of fundamental rights comparable to the constitutions of many Member States. Their initial emphasis was primarily economic: establishing a common market, removing barriers to trade, and creating common policies.

However, the expansion of Community authority created an unavoidable constitutional question. If Community law could affect individuals directly and prevail over conflicting national legislation, what legal guarantees would protect individuals against the exercise of Community power?

The Court of Justice gradually developed a system of fundamental rights protection through general principles of Community law.

12.1 Fundamental Rights as General Principles

In Case 29/69, Stauder v City of Ulm (1969), the Court recognised that fundamental rights formed part of the general principles of Community law and that their protection fell within the Court’s responsibility.

In Internationale Handelsgesellschaft, the Court confirmed that fundamental rights were protected as general principles derived from the constitutional traditions common to the Member States.

In Case 4/73, Nold v Commission (1974), the Court further explained that international treaties for the protection of human rights, to which Member States had cooperated or were signatories, could provide guidance in identifying the fundamental rights protected within the Community legal order.

These judgments established that the exercise of supranational authority was subject to fundamental rights requirements.

The development was important for two reasons.

First, it strengthened the legitimacy of the Community’s claim to primacy. A legal order exercising authority over individuals could not remain indifferent to fundamental rights.

Second, it established that rights protection was an internal requirement of Community law, rather than a matter left entirely to national constitutional systems.

12.2 The Charter of Fundamental Rights

The Charter of Fundamental Rights was proclaimed in 2000 and became legally binding with the entry into force of the Lisbon Treaty in 2009.

Article 6(1) TEU gives the Charter the same legal value as the Treaties.

It contains rights and principles relating to dignity, freedoms, equality, solidarity, citizens’ rights, and justice. Its provisions cover matters such as human dignity, privacy, data protection, freedom of expression, freedom of religion, non-discrimination, workers’ rights, and the right to an effective remedy.

The Charter applies to EU institutions, bodies, offices, and agencies in all their actions. It also applies to Member States when they are implementing or otherwise acting within the scope of EU law.

This limitation is crucial. The Charter does not create a general European jurisdiction over every question of national constitutional or human rights law. Article 51 makes clear that the Charter does not extend the competences of the Union.

The distinction preserves the division of powers between the EU and its Member States while ensuring that EU action respects fundamental rights.

12.3 The European Convention on Human Rights

The EU must also be understood in the wider European human rights framework.

The European Convention on Human Rights (ECHR) was adopted under the Council of Europe, an organisation separate from the European Union. All EU Member States are parties to the Convention.

The European Court of Human Rights, based in Strasbourg, supervises compliance with the Convention by its state parties. It is not an EU institution and must not be confused with the Court of Justice of the European Union in Luxembourg.

Article 6(2) TEU provides that the Union shall accede to the ECHR. However, accession has not yet been completed. The Court of Justice’s Opinion 2/13 found the draft accession agreement incompatible with EU law, and the subsequent negotiations have sought to address the objections identified by the Court.

The distinction between the two European courts is constitutionally important.

The Court of Justice interprets and applies EU law. The European Court of Human Rights interprets and applies the ECHR. Their jurisdictions are distinct, although their work frequently concerns related fundamental rights questions.

The EU’s fundamental rights framework therefore combines internal constitutional protection through the Charter and general principles with the broader European human rights system.

13. Democratic Legitimacy and the Constitutional Debate

The EU’s supranational character raises a difficult question: where does its democratic legitimacy come from?

In a conventional state, democratic authority is usually connected to a constitutional framework in which citizens elect representatives who exercise legislative and political power. The government is generally accountable to a national parliament, and the constitution defines the relationship between citizens and public authority.

The EU has a different structure.

Its democratic legitimacy derives from several connected sources:

1. The direct election of the European Parliament by EU citizens.
2. The participation of national governments in the Council and European Council.
3. The constitutional authority of the Member States, expressed through treaty ratification and amendment.
4. The participation of national parliaments in EU affairs.
5. The requirement that EU institutions act within the powers and procedures established by the Treaties.

Article 10 TEU states that the functioning of the Union is founded on representative democracy. Citizens are directly represented at Union level in the European Parliament, while Member States are represented in the European Council by their heads of state or government and in the Council by their governments, which are democratically accountable either to their national parliaments or to their citizens.

This creates a system of dual democratic representation: citizens are represented directly, while national political systems remain involved through their governments.

However, the arrangement has generated persistent debate.

13.1 The Democratic Deficit

The expression democratic deficit is used to describe perceived weaknesses in the democratic accountability and responsiveness of EU institutions.

Critics argue that EU decision-making can be distant from ordinary citizens, that institutional procedures are complex, and that responsibility for political decisions may be difficult to identify.

The Commission’s role in proposing legislation, the technical character of many EU measures, and the involvement of multiple institutions can make the legislative process difficult for the public to follow.

The Council’s role also raises questions about transparency and national accountability, particularly where ministers negotiate compromises at Union level that may be politically controversial within their own countries.

However, the democratic deficit debate must be considered in light of the Union’s actual institutional development.

The European Parliament’s powers have expanded considerably. Under the ordinary legislative procedure, Parliament and the Council act as co-legislators in a wide range of policy areas. Parliament also elects the Commission President following a proposal by the European Council, taking account of the European elections, and approves the Commission as a body.

The Lisbon Treaty also strengthened the role of national parliaments, particularly in relation to subsidiarity review.

The Union is therefore not a purely technocratic organisation. Its democratic structure is more developed than that of many traditional international organisations, although it remains different from the constitutional model of a state.

13.2 The European Union as a Constitutional System Without a State

The EU is sometimes described as a constitutional system without a state.

The expression captures an important feature of European integration. The Union has institutions, binding legal rules, judicial review, fundamental rights protection, and a distribution of public authority. Yet it does not possess the general sovereignty and constitutional structure of a traditional state.

Its constitutional development has occurred through treaty reform, institutional practice, legislation, and judicial interpretation rather than through the establishment of a single European sovereign constitution.

This has produced a system in which constitutional authority is shared and contested.

The Member States remain the authors of the Treaties, but the institutions created by those Treaties exercise autonomous powers. The Court of Justice interprets EU law as an independent legal order, while national constitutional courts continue to protect national constitutional principles.

The result is not a completed federal constitution. It is a plural constitutional structure in which different legal orders interact.

14. Constitutional Pluralism: The Interaction of European and National Legal Orders

Constitutional pluralism is a theoretical approach used to explain the coexistence of EU law and national constitutional law.

It begins with the recognition that the EU and its Member States possess legal systems with their own sources of authority, institutions, and constitutional principles.

The Court of Justice regards the Treaties as the foundation of an autonomous legal order whose rules must enjoy primacy to remain effective.

National constitutional courts, however, often regard their national constitutions as the ultimate source of authority for the transfer and exercise of public powers.

This creates two constitutional perspectives that do not always fit neatly into a single hierarchy.

14.1 The Court of Justice’s Perspective

From the perspective of the Court of Justice, EU law must be applied uniformly throughout the Union.

The Member States have accepted the Treaties and the legal consequences arising from them. They cannot unilaterally determine that a valid EU act is ineffective simply because a national authority disagrees with its interpretation or considers it constitutionally problematic.

The Court’s position is necessary to preserve the common legal framework. If each national constitutional court could independently determine the validity of EU law, the Union would risk becoming a collection of separate legal systems applying different versions of the same rules.

14.2 The National Constitutional Perspective

National constitutional courts approach the issue from the perspective of national constitutional authority.

They may accept the primacy of EU law in ordinary circumstances while maintaining that European integration cannot eliminate the essential constitutional identity of the state or authorise EU institutions to act outside the competences conferred upon them.

This approach is sometimes expressed through the doctrines of constitutional identity review and ultra vires review.

Constitutional identity review concerns whether an EU measure interferes with fundamental principles or structures protected by a national constitution.

Ultra vires review concerns whether an EU institution has acted beyond the powers conferred upon it by the Treaties.

These doctrines are not identical, and their scope differs between national constitutional systems.

They also create potential conflict with the Court of Justice’s insistence that the interpretation and validity of EU law must ultimately be determined within the Union’s judicial system.

14.3 Pluralism as a Description, Not an Automatic Solution

Constitutional pluralism is useful because it explains why the relationship between EU law and national constitutions cannot always be described through a simple vertical hierarchy.

However, it does not provide an automatic legal solution to every conflict.

If a national court refuses to apply an EU measure that the Court of Justice considers valid, the disagreement may threaten legal uniformity and the effectiveness of Union law.

Conversely, if the Union were able to disregard all national constitutional structures, it would undermine the principle that its authority is derived from powers conferred by the Member States.

The challenge is to preserve both the unity of EU law and the constitutional diversity recognised by the Treaties.

This is one of the defining constitutional questions of the European Union: how can a legal order exercise common authority without becoming a state, while preserving the constitutional autonomy of the states that created it?

15. Withdrawal, Sovereignty, and the Continuing Authority of the Member States

The legal nature of the EU also becomes clearer when considering the possibility of withdrawal.

Article 50 TEU provides that any Member State may decide to withdraw from the Union in accordance with its own constitutional requirements.

The withdrawing state must notify the European Council of its intention. The Union then negotiates an agreement setting out the arrangements for withdrawal, taking account of the framework for its future relationship with the Union.

The Treaties cease to apply to the state concerned from the date the withdrawal agreement enters into force or, failing that, two years after notification, unless the European Council, in agreement with the state concerned, unanimously decides to extend that period.

Article 50 demonstrates that membership of the EU is based on treaty commitments rather than an irreversible transfer of statehood.

The Member States have accepted substantial legal obligations and limitations on the exercise of their powers, but the Treaties expressly recognise a right to withdraw.

The United Kingdom’s withdrawal provides a practical illustration. Following the 2016 referendum, the United Kingdom notified the European Council under Article 50 in March 2017 and formally left the Union on 31 January 2020. The transition period ended on 31 December 2020.

Brexit demonstrated that withdrawal is legally possible, but it also revealed the complexity of disentangling a national legal system from a deeply integrated supranational order.

EU law had become embedded in legislation, administrative practice, judicial procedures, economic relationships, and individual rights. Withdrawal therefore required extensive legal arrangements concerning citizens’ rights, financial obligations, trade, regulatory cooperation, and the future relationship between the parties.

The significance of Article 50 is twofold.

First, it confirms that the Member States remain sovereign states capable of deciding whether to continue their participation in the Union, subject to their constitutional requirements and the withdrawal procedure.

Second, it demonstrates that membership creates a legal relationship of considerable depth. The exercise of the right to withdraw does not make the consequences of withdrawal simple or immediate.

The EU is therefore a durable supranational legal order, but not an irreversible federal state.

16. The European Union’s Distinctive Position Between International Law and Constitutionalism

The preceding principles reveal why no single traditional legal category fully captures the nature of the EU.

It has the international-law characteristics of an organisation established by treaty. Its Member States remain sovereign states, the Treaties determine its competences, and treaty revision depends upon procedures involving those states.

At the same time, it possesses constitutional characteristics that distinguish it from conventional international organisations.

Its institutions exercise legally defined powers independently of individual governments. Its legislation may operate directly within national legal systems. Its law may confer enforceable rights upon individuals. Its Court of Justice protects the autonomy and uniformity of the legal order. Its fundamental rights framework constrains public authority, and its institutional structure incorporates representative democracy.

The EU therefore occupies an intermediate position, but it should not be understood as merely halfway between an international organisation and a state.

It is a distinct legal and political construction with characteristics that do not fit comfortably within either traditional category.

The most useful way to understand it is through several complementary propositions:

The Union is treaty-based in origin. Its authority derives from agreements concluded by sovereign Member States.

The Union is supranational in operation. Its institutions exercise independent powers within the competences conferred upon them.

The Union is autonomous as a legal order. EU law has its own sources, judicial procedures, interpretative principles, and mechanisms of enforcement.

The Union has constitutional characteristics. The Treaties organise public authority, define institutional powers, protect fundamental rights, and establish principles governing the relationship between the Union and its Member States.

The Union remains limited by conferral. It does not possess the general sovereignty or unrestricted legislative competence of a state.

These characteristics are not contradictory. They are the defining elements of the EU’s distinctive constitutional structure.

The Union’s legal nature is consequently best understood as a form of supranational constitutionalism grounded in international treaties.

17. Why the Legal Nature of the EU Matters in Practice

The classification of the EU as a supranational legal order has practical consequences across almost every field of European law.

For individuals, it explains why certain rights arising under EU legislation or the Treaties can be enforced before national courts. A person may rely upon an applicable EU rule in proceedings against a public authority, subject to the conditions governing the particular provision.

For businesses, it explains why EU regulations may apply directly across Member States and why national legislation must comply with common rules concerning competition, consumer protection, data protection, product standards, and the internal market.

For national governments, it establishes that participation in the Union involves binding legal obligations. Governments cannot treat EU legislation as optional or disregard judgments of the Court of Justice without risking infringement proceedings and other legal consequences.

For national courts, it establishes a duty to apply EU law effectively, interpret domestic law consistently with EU obligations where possible, and refer appropriate questions to the Court of Justice.

For EU institutions, it establishes that their authority is neither unlimited nor purely political. Every institution must respect the Treaties, the allocation of competences, fundamental rights, and the institutional balance.

The legal nature of the EU therefore determines how European integration operates in everyday legal practice. It is not simply an academic debate about whether the Union resembles a federation or an international organisation. It concerns the source, scope, and limits of public authority in a legal system shared by 27 Member States.

Key Takeaways

1. The European Union is neither a state nor a conventional international organisation. It is a distinctive supranational legal and political structure established through international treaties.

2. The Treaties are its constitutional foundation. The TEU and TFEU establish the Union’s institutions, objectives, competences, procedures, and fundamental principles.

3. The EU possesses legal personality. Article 47 TEU enables it to act as an independent legal person in international and domestic legal relationships.

4. The EU legal order is autonomous. It has its own sources of law, judicial system, interpretative principles, and enforcement mechanisms.

5. Direct effect allows individuals to invoke certain EU provisions before national courts. The foundational judgment is Van Gend en Loos (1963).

6. Primacy requires EU law to prevail over conflicting national law within the scope of Union law. This principle was established in Costa v ENEL (1964) and clarified in subsequent judgments.

7. National courts are essential to the enforcement of EU law. Under the Simmenthal judgment, they must give effect to applicable EU law and disapply conflicting national provisions where required.

8. The Union’s powers are limited by conferral. It can act only within competences granted by the Treaties.

9. Subsidiarity and proportionality regulate the exercise of Union powers. They help determine whether action at EU level is justified and whether the measures adopted are appropriate.

10. The relationship between EU law and national constitutional law remains complex. The Court of Justice emphasises autonomy and primacy, while national constitutional courts continue to protect constitutional identity and the limits of transferred powers.

11. The EU has a constitutional dimension without being a sovereign state. Its Treaties organise public authority and protect fundamental rights, but the Member States retain their statehood and the powers not conferred upon the Union.

12. The legal nature of the EU is best described as a supranational constitutional order founded on international treaties.

Frequently Asked Questions

1. Is the European Union an international organisation or a state?

The European Union is neither a conventional international organisation nor a state. It was established through international treaties concluded by sovereign states, but it possesses an autonomous legal order with institutions capable of adopting binding rules, a judicial system, and legal principles that affect individuals and national legal systems. It is therefore generally described as a supranational political and legal union.

2. What does supranational mean in EU law?

Supranational means that Member States have established common institutions capable of exercising powers independently of individual national governments within defined areas of competence. EU institutions can adopt binding legal acts, sometimes through qualified majority voting, and those acts may produce legal effects throughout the Union. This distinguishes supranational cooperation from arrangements based exclusively on agreement between governments.

3. Why is the EU described as a new legal order?

The description originates in the judgment of the Court of Justice in Van Gend en Loos (Case 26/62, 1963). The Court held that the European Community constituted a new legal order of international law whose subjects included not only Member States but also their nationals. This meant that certain treaty provisions could create rights enforceable by individuals before national courts.

4. What is the difference between direct effect and primacy?

Direct effect concerns whether an individual can rely upon a provision of EU law before a court. Primacy concerns which rule must prevail when applicable EU law conflicts with national law. A provision may have direct effect if it satisfies the relevant legal conditions, while primacy ensures that conflicting national rules do not prevent the effective application of EU law.

5. Does EU law always prevail over national constitutions?

The Court of Justice maintains that EU law has primacy over national law, including constitutional provisions, within the scope of EU law. However, national constitutional courts have developed approaches concerning constitutional identity and the limits of competences transferred to the Union. These positions have generated important constitutional debates. Article 4(2) TEU requires respect for national identity, but it does not provide an unrestricted right for Member States to disregard EU law unilaterally.

6. Does the European Union have its own constitution?

The EU does not have a single constitution in the traditional state-based sense. Instead, its constitutional framework is primarily contained in the TEU and TFEU, supplemented by protocols, the Charter of Fundamental Rights, and general principles of EU law. These instruments perform many functions associated with national constitutions, including organising institutions, allocating powers, and protecting rights.

7. What is the legal personality of the European Union?

Article 47 TEU provides that the Union has legal personality. This allows it to conclude international agreements, own property, enter contracts, participate in legal proceedings, and exercise other legal capacities within its competences. Legal personality does not make the EU a sovereign state or grant it unlimited powers.

8. Can the EU legislate in any area it considers important?

No. Under the principle of conferral in Article 5 TEU, the Union may act only within competences granted to it by the Treaties. These include exclusive, shared, and supporting or coordinating competences. Areas not conferred upon the Union remain within the competence of the Member States, subject to their obligations under EU law.

9. What is the role of the Court of Justice in maintaining the EU legal order?

The Court of Justice ensures that EU law is interpreted and applied consistently. It reviews the legality of acts adopted by EU institutions, interprets EU law through preliminary rulings, and resolves certain disputes involving Member States and Union institutions. Its case law has been central to the development of direct effect, primacy, autonomy, and fundamental rights protection.

10. Can a Member State leave the European Union?

Yes. Article 50 TEU establishes a procedure through which a Member State may withdraw in accordance with its constitutional requirements. The United Kingdom exercised this right and formally left the Union on 31 January 2020. Withdrawal demonstrates that EU membership is based on treaty commitments, although the legal and economic consequences of leaving can be extensive.

11. Is the EU becoming a federal state?

European integration has developed several federal characteristics, including shared competences, common institutions, binding legislation, and judicial enforcement. Nevertheless, the EU does not possess the general sovereignty of a federal state. Its authority remains based on competences conferred by Member States, which retain their national constitutions, political institutions, and statehood. Whether further integration should move towards a federal model remains a political and constitutional question.

12. What is constitutional pluralism in EU law?

Constitutional pluralism describes the coexistence and interaction of the EU legal order and the constitutional systems of its Member States. The Court of Justice emphasises the autonomy and primacy of EU law, while national constitutional courts maintain that national constitutions remain important sources of constitutional authority. The concept helps explain the continuing dialogue and occasional conflict between European and national courts.

Conclusion

The European Union represents one of the most distinctive developments in modern legal and political organisation. It emerged through international agreements between sovereign states, yet it developed into a legal order whose rules can operate directly within national legal systems, create enforceable rights for individuals, and take precedence over conflicting domestic legislation.

Its constitutional character is not the product of a single founding document or a declaration establishing a European state. It has developed through treaty reform, institutional practice, legislation, and judicial interpretation. The judgments in Van Gend en Loos, Costa v ENEL, Internationale Handelsgesellschaft, and Simmenthal transformed the original Community framework into a legal system with characteristics that traditional international law could not fully explain.

Nevertheless, the Union remains grounded in the principle of conferral. It does not possess general sovereignty, and the Member States continue to determine the fundamental limits of its authority through the Treaties. The relationship between European law and national constitutional systems therefore remains one of cooperation, interdependence, and occasional constitutional tension.

The most accurate description of the European Union is consequently neither a state nor an ordinary international organisation. It is an autonomous supranational legal order with constitutional characteristics, established by international treaties and operating through a distinctive system of shared authority.

Its importance lies precisely in this combination. The EU demonstrates that states can create a common legal system capable of exercising public authority beyond the traditional boundaries of national government without necessarily dissolving their separate constitutional identities. Whether this arrangement ultimately develops into a more federal structure or preserves its present hybrid character remains one of the central questions in European constitutional law.

Official Legal Sources and Further Reading

Foundational Treaties and EU legal instruments

• Consolidated Treaty on European Union (TEU) — particularly Articles 1, 2, 4, 5, 6, 10, 13, 47 and 48.
• Treaty on the Functioning of the European Union (TFEU) — particularly Articles 2–6, 114, 216, 267 and 288.
• Charter of Fundamental Rights of the European Union.
• Declaration No 17 concerning primacy.

Foundational judgments and jurisprudence

• Van Gend en Loos v Nederlandse Administratie der Belastingen, Case 26/62 (1963).
• Costa v ENEL, Case 6/64 (1964).
• Internationale Handelsgesellschaft, Case 11/70 (1970).
• Simmenthal, Case 106/77 (1978).
• Les Verts v European Parliament, Case 294/83 (1986).
• Opinion 2/13 on EU accession to the ECHR (2014).
• RS, Case C-430/21 (2022).

Institutional explanations

• Court of Justice of the European Union — Fundamental Cases.
• European Parliament — Sources and Scope of EU Law.
• EUR-Lex — Primacy of EU Law.
• European Commission — The ABC of EU Law.