The Constitutional Treaty of 2004: The European Constitution That Never Entered into Force

The Constitutional Treaty of 2004: The European Constitution That Never Entered into Force

Introduction

The Treaty establishing a Constitution for Europe, signed in Rome on 29 October 2004, was one of the most ambitious attempts to reform the constitutional structure of European integration. It sought to replace the complex collection of treaties governing the European Union with a single, more coherent constitutional instrument. Its purpose was not simply to amend existing provisions, but to reorganise the Union’s institutions, clarify its competences, strengthen democratic accountability, incorporate the Charter of Fundamental Rights into the treaty framework, and give the EU a more recognisable constitutional identity.

The project emerged from a growing recognition that the institutional arrangements developed for a Community of six Member States were increasingly difficult to operate in a Union approaching twenty-five. The successive enlargements, the introduction of the euro, the development of common policies, and the expansion of cooperation into foreign affairs, security, justice, and home affairs had produced a legal order of considerable complexity. The Treaty of Maastricht had created the European Union and its pillar structure; the Treaties of Amsterdam and Nice had modified that structure, but neither had resolved all the institutional questions raised by enlargement.

The Constitutional Treaty was intended to address these difficulties through a comprehensive settlement. It proposed a clearer division of competences between the Union and its Member States, a more consistent institutional system, a permanent President of the European Council, a strengthened role for the European Parliament, a reformed system of qualified majority voting, and a single legal personality for the Union. It also sought to make the Union’s fundamental values and rights more visible within its constitutional framework.

Yet the Treaty never entered into force. Although it was signed by all twenty-five Member States, it required ratification by every state according to its own constitutional procedures. In May and June 2005, voters in France and the Netherlands rejected it in national referendums. The resulting political crisis halted the ratification process and led the Member States to reconsider the form and substance of institutional reform. Many of the Constitutional Treaty’s provisions were eventually incorporated, in modified form, into the Treaty of Lisbon, which entered into force on 1 December 2009.

The Constitutional Treaty therefore occupies a distinctive position in European legal history. It was not an operative constitution and did not replace the existing treaties. Nevertheless, it remains essential to understanding the constitutional development of the European Union. Its drafting process, substantive provisions, rejection, and eventual influence on the Lisbon Treaty reveal both the possibilities and the limits of constitutional reform within a Union founded on agreements between sovereign states.

1. The Political and Institutional Background

1.1 An enlarged Union and an increasingly complex legal structure

By the beginning of the twenty-first century, European integration had developed far beyond the economic cooperation envisaged by the Treaties of Rome. The European Communities had acquired extensive responsibilities in areas such as the internal market, competition, agriculture, trade, environmental protection, and economic and monetary cooperation. The Maastricht Treaty had added the European Union as a broader political and legal framework, while the Amsterdam Treaty had transferred certain matters relating to visas, asylum, immigration, and civil judicial cooperation into the Community framework.

However, the institutional structure remained difficult to understand. The European Union operated through several overlapping treaty arrangements. The European Community had its own legal personality, while the Union’s activities under the Common Foreign and Security Policy and the former Justice and Home Affairs pillar followed different legal and institutional rules. The distinction between supranational and intergovernmental decision-making was reflected in the allocation of powers, the role of the institutions, and the procedures available for judicial review.

The treaty framework had also become difficult for non-specialists to navigate. Each major reform had amended earlier instruments rather than replacing them with a single consolidated constitutional text. The result was a body of primary law consisting of several treaties, protocols, declarations, amendments, and accession instruments.

This complexity was not merely a matter of presentation. It affected institutional decision-making and raised questions about transparency, democratic legitimacy, and the relationship between the Union and its Member States.

1.2 Enlargement towards Central and Eastern Europe

The prospect of the 2004 enlargement gave urgency to institutional reform. Ten states joined the European Union on 1 May 2004:

• Cyprus;
• the Czech Republic;
• Estonia;
• Hungary;
• Latvia;
• Lithuania;
• Malta;
• Poland;
• Slovakia; and
• Slovenia.

The enlargement represented a major political and historical development, bringing together states that had followed different political and economic paths during the Cold War. It also significantly increased the size of the Union and the number of governments participating in its institutions.

The existing arrangements had been designed for a much smaller membership. Questions concerning the size and composition of the Commission, the allocation of voting weights in the Council, the presidency of the European Council, and the operation of qualified majority voting became increasingly important.

The Treaty of Nice, which entered into force in 2003, had introduced institutional adjustments intended to prepare the Union for enlargement. Nevertheless, many governments and political actors regarded the Nice settlement as incomplete. It had addressed immediate institutional pressures but had not produced a comprehensive constitutional framework.

1.3 The Declaration on the Future of the European Union

The political process leading to the Constitutional Treaty began with the Declaration on the Future of the European Union, adopted at the European Council meeting in Laeken, Belgium, in December 2001.

The Laeken Declaration identified several questions concerning the future of European integration. These included how to bring citizens closer to the European institutions, how to improve the allocation of competences, how to simplify the Union’s legal instruments, and how to strengthen democratic legitimacy and accountability.

It also raised the question of whether the existing treaty framework should be reorganised into a more coherent constitutional text.

The declaration reflected an important change in the nature of treaty reform. Earlier revisions had generally been negotiated through intergovernmental conferences involving national governments. The Laeken process instead established a Convention that included representatives from national governments, national parliaments, the European Parliament, and the European Commission.

This broader composition was intended to make the reform process more transparent and politically inclusive.

2. The European Convention and the Drafting Process

2.1 Establishment and composition

The European Convention on the Future of Europe began its work in February 2002 under the presidency of former French President Valéry Giscard d’Estaing. It included representatives of the governments and parliaments of the Member States and candidate countries, as well as representatives of the European Parliament and the European Commission.

The Convention was not a constituent assembly in the classical constitutional sense. It did not possess independent sovereign authority to enact a constitution for Europe. Its task was to examine the questions identified in the Laeken Declaration and prepare proposals for the next stage of treaty reform.

Nevertheless, its composition distinguished it from a conventional diplomatic conference. National parliamentarians participated directly in the drafting process, alongside representatives of governments and European institutions. Candidate countries also took part, although their representatives did not have the same decision-making position as those representing existing Member States.

The Convention established working groups and examined a wide range of institutional, constitutional, and policy questions. Its deliberations included the division of competences, the role of national parliaments, the future of the Charter of Fundamental Rights, the Union’s external representation, and the simplification of its legal instruments.

2.2 The draft Constitutional Treaty

The Convention presented its draft Treaty establishing a Constitution for Europe in July 2003. The draft was then considered by an intergovernmental conference, which began negotiations in October 2003.

The negotiations were politically difficult. Member States disagreed over the allocation of voting power in the Council, the composition of the Commission, the extent of qualified majority voting, and the institutional balance between larger and smaller states.

The European Council meeting in Brussels in December 2003 failed to reach agreement. Negotiations resumed in 2004, and the Member States eventually reached a political compromise at the European Council meeting of 17–18 June 2004.

The final text was signed in Rome on 29 October 2004 by the representatives of the twenty-five Member States.

The signing was symbolically significant. Rome was the city in which the Treaties establishing the European Economic Community and Euratom had been signed in 1957. The location therefore connected the proposed constitutional settlement with the historical foundations of European integration.

However, signature did not make the Constitutional Treaty legally operative. It remained subject to ratification by all Member States.

3. The Legal Nature of the Constitutional Treaty

3.1 Was it a constitution in the traditional sense?

The title of the instrument raised an important constitutional question. The Treaty was called a Constitution, but its legal form remained that of an international treaty concluded between sovereign states.

It was not adopted through a single European constituent act independent of the Member States. Its entry into force depended on ratification by every signatory state in accordance with its national constitutional requirements.

This distinction is essential. A constitution may establish the legal framework of a state, define public institutions, allocate governmental powers, and protect fundamental rights. The Constitutional Treaty sought to perform some comparable functions for the European Union. Nevertheless, it did not transform the Union into a state or establish a federal government with general sovereign authority.

Its legal authority would have derived from the consent of the Member States expressed through ratification. The Union would have continued to exercise only those competences conferred upon it by the treaties.

The Constitutional Treaty was therefore constitutional in its subject matter and ambition, but treaty-based in its legal foundation.

3.2 The relationship between the Union and its Member States

The proposed Constitution did not abolish the Member States or replace their constitutional systems. It expressly recognised that the Union’s powers were based on the principle of conferral.

Under that principle, the Union could act only within the limits of the competences attributed to it by the Member States. Powers not conferred upon the Union would remain with the Member States.

The proposed text also recognised national constitutional identities and the continuing responsibilities of Member States for essential state functions, including territorial integrity, public order, and national security.

The relationship was therefore not one of unrestricted central authority. The proposed constitutional structure attempted to combine the effectiveness of common European institutions with the continuing constitutional autonomy of the Member States.

3.3 A single constitutional instrument

One of the most important objectives was to simplify the Union’s legal framework.

The Constitutional Treaty was designed to replace the existing principal treaties with a single instrument organised into four parts:

1. Part I: constitutional provisions and the basic structure of the Union;
2. Part II: the Charter of Fundamental Rights of the European Union;
3. Part III: the policies and functioning of the Union;
4. Part IV: general and final provisions.

This arrangement would have brought together provisions that had previously been dispersed across the Treaty on European Union, the Treaty establishing the European Community, and other treaty instruments.

The proposed Constitution also included protocols and declarations. These formed part of the broader legal settlement and addressed matters such as institutional arrangements, subsidiarity, national parliaments, and specific Member State positions.

The simplification was substantial in presentation, although the resulting text remained lengthy and technically complex. The constitutional ambition did not eliminate the need for detailed legal rules governing the Union’s policies and institutions.

4. The Main Constitutional Innovations

4.1 A single legal personality for the European Union

One of the most significant innovations was the proposed creation of a single legal personality for the European Union.

Under the pre-existing structure, the European Community possessed legal personality, while the European Union under the Maastricht framework did not have a general legal personality equivalent to that of the Community. This distinction complicated the Union’s external representation and the legal organisation of its international activities.

The Constitutional Treaty proposed to give the Union legal personality in its own right and to replace the European Community with the Union.

This would have allowed the Union to act as a single legal entity in its external relations, subject to the competences conferred upon it. It could conclude international agreements, participate in international organisations where legally appropriate, and represent its interests through a more coherent institutional structure.

The proposal was not intended to give the Union unlimited international authority. Its capacity to act externally would still have depended on the division of competences between the Union and its Member States.

The innovation was primarily one of legal coherence and institutional representation.

4.2 The abolition of the pillar structure

The Maastricht Treaty had established a three-pillar structure:

• the European Communities;
• the Common Foreign and Security Policy; and
• Justice and Home Affairs, later renamed Police and Judicial Cooperation in Criminal Matters.

The pillars followed different decision-making and judicial arrangements. The Community pillar was predominantly supranational, while the second and third pillars retained stronger intergovernmental characteristics.

The Constitutional Treaty proposed to abolish this formal structure and establish a more unified Union framework.

This did not mean that all policy areas would become subject to identical procedures. The proposed Constitution retained special arrangements for certain areas, particularly foreign and security policy. However, the abolition of the pillars would have reduced the formal division between different legal structures and made the Union’s institutional organisation more coherent.

The reform was significant because it sought to replace a system of parallel institutional arrangements with a single Union framework while preserving policy-specific distinctions where necessary.

4.3 The principle of conferral and the classification of competences

The Constitutional Treaty sought to make the distribution of powers between the Union and its Member States easier to understand.

It expressly classified Union competences into three principal categories:

Exclusive competences. In these areas, the Union alone could legislate and adopt legally binding acts, subject to the conditions laid down in the Constitution. Member States could act only where authorised by the Union or where implementing Union law.

Shared competences. In these areas, both the Union and the Member States could legislate and adopt legally binding acts. Member States could exercise their competence to the extent that the Union had not exercised its own competence, or where the Union had decided to cease exercising it.

Supporting, coordinating, or complementary competences. In these areas, the Union could support or coordinate Member State action but could not replace national competence or harmonise national laws where the Constitution prohibited harmonisation.

The proposed classification aimed to make the limits of Union authority more visible. It also connected the allocation of powers with the principles of subsidiarity and proportionality.

The classification did not create a general power for the Union to act whenever a common European solution appeared desirable. The legal basis for Union action still had to be found in the constitutional text.

4.4 Subsidiarity and proportionality

The Constitutional Treaty retained and developed the principles of subsidiarity and proportionality.

Subsidiarity governed the exercise of non-exclusive Union competences. It required the Union to act only where the objectives of the proposed action could not be sufficiently achieved by the Member States, whether at central, regional, or local level, and could be better achieved at Union level because of the scale or effects of the proposed action.

Proportionality required Union action not to exceed what was necessary to achieve the objectives established by the Constitution.

The proposed framework also strengthened the role of national parliaments in monitoring subsidiarity. They were to receive draft legislative acts and could issue reasoned opinions where they considered that a proposal did not comply with the principle.

This mechanism became known as the early-warning system. It was designed to introduce national parliamentary scrutiny into the European legislative process before a measure was adopted.

The reform reflected an attempt to reconcile common European decision-making with the constitutional responsibilities of national democratic institutions.

4.5 The Charter of Fundamental Rights

The Constitutional Treaty incorporated the Charter of Fundamental Rights of the European Union as Part II of the proposed Constitution.

The Charter had originally been proclaimed in December 2000 by the European Parliament, the Council, and the Commission. Before the Constitutional Treaty, it did not possess the same binding treaty status as the principal provisions of the Union’s primary law.

Incorporating it into the Constitutional Treaty would have given it binding legal force within the proposed constitutional framework.

The Charter brought together civil, political, economic, and social rights recognised within the Union’s legal order. Its provisions addressed dignity, freedoms, equality, solidarity, citizens’ rights, and justice.

The incorporation was constitutionally significant because it made fundamental rights more visible as an integral part of the Union’s legal structure.

The Charter did not, however, create an unrestricted human-rights jurisdiction for the Union. Its scope was linked to the application of Union law. The proposed constitutional provisions also preserved the distinction between the Union’s legal framework and the European Convention on Human Rights.

The Constitutional Treaty’s failure did not permanently prevent the Charter from acquiring binding force. The Treaty of Lisbon later gave the Charter the same legal value as the Treaties through Article 6(1) of the Treaty on European Union.

4.6 The primacy of Union law

The Constitutional Treaty expressly included a provision on the primacy of Union law.

It stated that the Constitution and law adopted by the Union institutions in exercising competences conferred upon the Union would have primacy over the law of the Member States.

This provision was politically sensitive because it placed an established judicial doctrine into the text of a proposed constitutional instrument.

The Court of Justice had developed the principle of primacy through its case law, particularly in Costa v ENEL (Case 6/64). The Court reasoned that the legal order created by the European Community could not be overridden by conflicting national law without undermining its effectiveness.

The Constitutional Treaty did not invent the principle. It sought to state it expressly in the constitutional text.

The provision became one of the subjects of political debate surrounding the Treaty, particularly in discussions about national sovereignty and the relationship between European and domestic constitutional law.

4.7 A more visible democratic structure

The Constitutional Treaty proposed several reforms intended to strengthen democratic legitimacy and institutional accountability.

The European Parliament would continue to exercise legislative and budgetary functions jointly with the Council in an expanded range of policy areas. The ordinary legislative procedure would become more widely applicable, replacing the term “co-decision” with a more general legislative framework.

The role of national parliaments would also be strengthened through the subsidiarity-monitoring mechanism.

In addition, the proposed Constitution recognised the principle of participatory democracy and provided for a citizens’ initiative. Under the proposed mechanism, a significant number of citizens from a substantial number of Member States could invite the Commission to submit an appropriate proposal on a matter within its powers.

The initiative did not give citizens a direct legislative power. It was a mechanism for requesting that the Commission consider proposing legislation.

The proposed reforms reflected the view that democratic legitimacy in the Union could not depend solely on the participation of national governments in the Council. It also required meaningful parliamentary representation, public accountability, and opportunities for citizen participation.

4.8 A permanent President of the European Council

The Constitutional Treaty proposed creating the office of a permanent President of the European Council.

Before this reform, the European Council was chaired by the head of state or government of the Member State holding the rotating Council Presidency. The system provided each Member State with an opportunity to lead the European Council, but it also meant that the Union’s highest political forum changed its chair every six months.

The proposed Constitution would replace this arrangement with a President elected by the European Council for a term of two and a half years, renewable once.

The President’s responsibilities would include chairing and coordinating the work of the European Council, ensuring continuity in its activities, facilitating cohesion and consensus, and representing the Union at the level of heads of state or government in matters concerning the Common Foreign and Security Policy, without prejudice to the powers of the proposed Union Minister for Foreign Affairs.

The purpose was to provide greater continuity in the Union’s political leadership and improve its capacity to develop a consistent strategic direction.

The office was subsequently established under the Treaty of Lisbon, although its precise legal framework was modified.

4.9 The Union Minister for Foreign Affairs

Another important proposal was the creation of a Union Minister for Foreign Affairs.

The office was designed to combine functions previously divided between the High Representative for the Common Foreign and Security Policy and the European Commissioner responsible for external relations.

The Minister would participate in the work of the Council, contribute to the development of the Union’s foreign and security policy, and serve as a Vice-President of the Commission. This dual institutional position was intended to improve coordination between the intergovernmental and supranational dimensions of external action.

The proposal reflected a longstanding problem in the Union’s international representation. The EU had developed significant economic and diplomatic influence, but its external voice was often divided between the Commission, the Council Presidency, the High Representative, and national governments.

A single office combining these responsibilities was intended to improve coherence, although the Member States would continue to retain important powers in foreign and security policy.

The Treaty of Lisbon later established the office of High Representative of the Union for Foreign Affairs and Security Policy, incorporating much of the proposed institutional design but retaining a different title.

4.10 Reform of the European Commission

The Constitutional Treaty also addressed the composition and functioning of the European Commission.

The Commission was to consist of a President, the Union Minister for Foreign Affairs as one of its Vice-Presidents, and a number of other Commissioners. The proposed arrangement included a distinction between full members of the Commission and Commissioners without voting rights under the rotation system.

The objective was to prevent the Commission from becoming excessively large as the Union expanded. A body containing one voting Commissioner for every Member State could become difficult to coordinate and might complicate the principle that Commissioners act in the general interest of the Union rather than as national representatives.

The proposed rotation system was intended to ensure equality between Member States while maintaining the Commission’s capacity to operate effectively.

The issue was politically sensitive. Member States differed over whether every state should retain a Commissioner at all times. The composition of the Commission was not simply an administrative question; it concerned the perceived equality of states within the institutional structure.

The final Lisbon settlement retained the possibility of a smaller Commission, but the practical arrangements were subsequently affected by political decisions and the commitment made in connection with the Irish referendum process.

4.11 Reform of voting in the Council

The Constitutional Treaty proposed a new system of qualified majority voting in the Council.

Under the proposed system, a qualified majority would generally require the support of at least 55 per cent of the Member States, comprising at least fifteen states, and representing at least 65 per cent of the population of the Union. A blocking minority would have to include at least four Council members.

This double-majority model was designed to reflect two dimensions of representation: the equality of Member States as sovereign participants and the demographic weight of the Union’s population.

It replaced the more complicated system of weighted votes established under the Treaty of Nice.

The reform was intended to make Council voting easier to understand and to improve the Union’s ability to make decisions after enlargement. However, the distribution of voting power was a contentious issue, particularly between larger and smaller Member States.

The Lisbon Treaty later adopted a comparable double-majority system, although its application was subject to transitional arrangements.

4.12 Expansion of qualified majority voting and the ordinary legislative procedure

The Constitutional Treaty proposed extending qualified majority voting to additional areas of Union activity. It also expanded the legislative procedure in which the European Parliament and the Council would act jointly.

The existing co-decision procedure was to become the ordinary legislative procedure. This change reflected the development of the European Parliament from a largely consultative assembly into a directly elected institution with substantial legislative authority.

Under the proposed ordinary legislative procedure, the Commission would generally submit a legislative proposal, and the European Parliament and Council would consider and adopt the measure on an equal legislative footing, subject to the detailed procedural rules.

The reform was intended to reduce the areas in which national governments could block legislation through unanimity and to strengthen the democratic dimension of Union law-making.

However, the Constitutional Treaty did not eliminate unanimity. Certain particularly sensitive policy areas would continue to require unanimous agreement, reflecting the Member States’ reluctance to transfer decision-making authority in every field.

4.13 The European Parliament and democratic accountability

The Constitutional Treaty proposed strengthening the European Parliament’s role in the Union’s institutional system.

It extended the ordinary legislative procedure, increased Parliament’s involvement in the budgetary process, and maintained its role in approving the President of the Commission and the Commission as a body.

The Parliament would also continue to exercise political supervision through parliamentary questions, debates, committees, and the possibility of adopting a motion of censure against the Commission.

These changes were part of a broader effort to address the democratic deficit often discussed in connection with European integration. The expression refers to concerns that decisions affecting citizens were sometimes made through complex institutional procedures that appeared remote from direct electoral control.

The Constitutional Treaty did not resolve every question concerning democratic legitimacy. The European Parliament remained only one component of the Union’s democratic structure, alongside national parliaments and the governments represented in the Council and European Council. Nevertheless, the proposed reforms sought to make parliamentary participation more central to the legislative process.

4.14 The citizens’ initiative

The Constitutional Treaty introduced the idea of a European citizens’ initiative.

Under the proposed provision, at least one million citizens who were nationals of a significant number of Member States could invite the Commission to submit an appropriate proposal on a matter where they considered that a legal act of the Union was required to implement the Constitution.

The initiative was not a referendum mechanism and did not allow citizens to enact legislation directly. The Commission would remain responsible for deciding whether to submit a legislative proposal, within the limits of its powers and the applicable legal requirements.

Its constitutional importance lay in the recognition that citizens could participate in setting the legislative agenda, rather than being involved only through elections and consultation.

The mechanism was later retained in the Lisbon Treaty and developed through secondary legislation. It became one of the most recognisable examples of participatory democracy at Union level.

5. The Union’s Fundamental Values, Objectives, and Symbols

The Constitutional Treaty sought to express the political and constitutional identity of the Union more clearly.

It identified the values on which the Union was founded, including human dignity, freedom, democracy, equality, the rule of law, and respect for human rights, including the rights of persons belonging to minorities.

It also referred to a society characterised by pluralism, non-discrimination, tolerance, justice, solidarity, and equality between women and men.

These values were not presented merely as political aspirations. They formed part of the proposed constitutional framework and were connected to the conditions of membership, the conduct of Union institutions, and the Union’s external relations.

The Constitution also set out the Union’s objectives. These included promoting peace, its values, and the well-being of its peoples; offering an area of freedom, security, and justice without internal frontiers; establishing an internal market; and working towards sustainable development based on balanced economic growth and price stability.

The text also proposed recognising certain symbols of the Union: the European flag, the European anthem, the motto “United in diversity,” Europe Day on 9 May, and the euro as the currency of the Union.

The inclusion of symbols was politically significant. It made the constitutional project more visible and contributed to the perception that the Union was developing an identity beyond that of a conventional economic organisation.

For supporters of the project, these provisions expressed a shared political community. For critics, they raised questions about the extent to which the Union should acquire the symbolic characteristics traditionally associated with a state.

The issue became part of the wider political debate about the meaning of the word “constitution” and the future direction of European integration.

6. The Common Foreign and Security Policy and External Action

The Constitutional Treaty sought to improve the coherence of the Union’s external action.

The proposed Union Minister for Foreign Affairs would have occupied a central position in the development and implementation of the Common Foreign and Security Policy. The Treaty also sought to coordinate the Union’s diplomatic, economic, humanitarian, and security-related activities.

The Constitution retained the special character of the Common Foreign and Security Policy. Although the formal pillar structure would have been abolished, foreign and security policy would continue to involve significant intergovernmental decision-making and special procedural rules.

The proposed provisions also addressed the gradual development of a common security and defence policy. They provided for mutual assistance in the event of armed aggression against a Member State, subject to the specific constitutional and international obligations of the states concerned.

The Treaty further contemplated structured cooperation among Member States willing and able to undertake more demanding military commitments.

These provisions reflected the ambition to develop a more coherent European role in international affairs while recognising that national governments retained fundamental responsibilities for defence and security.

The proposed Constitution did not establish a European army or transfer general control of national armed forces to the Union. Defence remained a particularly sensitive area of national sovereignty.

7. Justice, Freedom, and Security

The Constitutional Treaty proposed further integration in the area of freedom, security, and justice.

This policy field had developed considerably since the Maastricht Treaty. It included matters relating to external border controls, asylum, immigration, judicial cooperation in civil matters, police cooperation, and judicial cooperation in criminal matters.

The proposed Constitution sought to establish a more coherent legal framework for these activities and to extend the use of ordinary legislative procedures and qualified majority voting in several areas.

It also strengthened the role of the European Parliament and the Court of Justice in relevant fields, although special provisions and limitations remained.

The constitutional objective was to create an area in which individuals could move freely while benefiting from coordinated arrangements for border management, judicial cooperation, and law enforcement.

The reform was particularly important because the abolition of the pillar structure would have reduced the institutional separation between Community policies and the former Justice and Home Affairs framework.

Nevertheless, the proposed system did not eliminate national responsibility for criminal justice, policing, or immigration administration. It sought to organise cooperation and common rules within the competences attributed to the Union.

8. Why the Constitutional Treaty Was Rejected

8.1 The ratification requirement

The Constitutional Treaty was signed by all twenty-five Member States in October 2004. It could enter into force only after ratification by every signatory state in accordance with its constitutional requirements.

This requirement reflected the treaty-based nature of the European Union. The proposed constitutional settlement depended on the agreement of all Member States, rather than on a direct act of a European sovereign authority.

Several states completed their ratification procedures, some through parliamentary approval and others through referendums. Spain, for example, approved the Treaty in a referendum held in February 2005, although the referendum was consultative in character and parliamentary ratification was still required.

The process encountered a decisive obstacle in France and the Netherlands.

8.2 The French referendum of 29 May 2005

On 29 May 2005, French voters rejected the Constitutional Treaty in a national referendum.

Approximately 54.7 per cent voted against ratification, while approximately 45.3 per cent voted in favour.

The result was politically significant because France had been one of the central states in the development of European integration. Its rejection demonstrated that support for the European project did not necessarily translate into support for every proposed institutional reform.

The referendum campaign involved several different concerns. These included questions about national sovereignty, the economic and social direction of the Union, the perceived consequences of enlargement, the relationship between European integration and national employment, and the complexity of the constitutional text.

The result should not be reduced to a single explanation. Voters approached the referendum from different political and social perspectives, and the campaign included arguments that were not confined to the legal content of the Treaty itself.

8.3 The Dutch referendum of 1 June 2005

Three days later, on 1 June 2005, Dutch voters also rejected the Constitutional Treaty.

Approximately 61.5 per cent voted against it, while approximately 38.5 per cent supported ratification.

The Dutch referendum was the first national referendum on European integration in the Netherlands. The result reflected a combination of concerns, including the perceived transfer of authority to European institutions, the speed and direction of integration, the role of national identity, and dissatisfaction with aspects of the political process.

As in France, the vote cannot be interpreted as a simple rejection of European cooperation. It was a rejection of the particular constitutional settlement submitted to the electorate.

The two negative referendums created a legal and political obstacle that could not be overcome through the ratification decisions of other Member States.

8.4 The consequences of the two negative votes

The Constitutional Treaty required unanimous ratification. Once France and the Netherlands rejected it, the conditions for entry into force could no longer be fulfilled under the existing ratification process.

Other Member States had already ratified the Treaty or were continuing their national procedures. The Council’s official treaty record shows that several ratifications were notified after the French and Dutch referendums. Nevertheless, these approvals could not compensate for the absence of unanimous ratification.

The Treaty therefore never became binding primary law of the European Union.

The European Council responded by initiating a period of reflection. At its June 2005 meeting, the heads of state or government acknowledged the results and recognised the need for further discussion about the future of European integration.

The constitutional project was not immediately abandoned in every respect. Instead, the Member States began considering whether the institutional reforms could be preserved through a different treaty structure.

The failure of ratification demonstrated the limits of constitutional reform where the legal order continues to depend on unanimous agreement between sovereign states.

9. From Constitutional Treaty to Treaty of Lisbon

9.1 The period of reflection

Following the French and Dutch referendums, the European Council decided in June 2005 to initiate a period of reflection. The intention was to consider the political implications of the rejection and determine how the Union should proceed with institutional reform.

The period did not produce an immediate agreement on a new constitutional settlement. Member States differed over whether the Constitutional Treaty should be abandoned, renegotiated, or preserved in some form.

The debate also exposed a distinction between the substance of the proposed reforms and the constitutional form in which they had been presented. Many governments continued to support institutional changes designed to improve the Union’s efficiency and democratic accountability. However, the language and symbolism of a European Constitution had become politically difficult.

The Berlin Declaration of 25 March 2007, adopted on the fiftieth anniversary of the Treaties of Rome, reaffirmed the Member States’ commitment to European integration and provided political momentum for renewed negotiations.

9.2 The 2007 mandate for a Reform Treaty

At the European Council meeting of 21–22 June 2007, the Member States agreed on a mandate for a new Intergovernmental Conference.

Rather than producing another single constitutional text, the conference was instructed to amend the existing treaties. This approach preserved the traditional form of treaty revision and avoided presenting the reform as the adoption of a European Constitution.

The negotiations produced the Treaty of Lisbon, signed on 13 December 2007. It entered into force on 1 December 2009, after ratification by all Member States.

The Lisbon Treaty therefore did not revive the Constitutional Treaty as originally drafted. It adopted a different legal technique: amending the Treaty on European Union and the Treaty establishing the European Community, the latter being renamed the Treaty on the Functioning of the European Union.

The European Community was succeeded by the European Union, which acquired express legal personality under Article 47 TEU.

9.3 Which constitutional reforms survived?

A considerable number of the Constitutional Treaty’s institutional and legal reforms were retained in the Lisbon settlement.

Constitutional Treaty proposal	Position under the Treaty of Lisbon
Single legal personality for the Union	Adopted through Article 47 TEU
Abolition of the pillar structure	Adopted, although special CFSP arrangements remain
Permanent President of the European Council	Adopted
Union Minister for Foreign Affairs	Replaced by the High Representative of the Union for Foreign Affairs and Security Policy
Double-majority voting in the Council	Adopted, subject to transitional arrangements
Wider use of the ordinary legislative procedure	Substantially retained and extended
Stronger role for national parliaments	Retained, including subsidiarity scrutiny
European citizens’ initiative	Retained and subsequently implemented
Charter of Fundamental Rights	Given the same legal value as the Treaties under Article 6(1) TEU
Explicit constitutional primacy clause	Not reproduced as a treaty article; primacy was addressed in Declaration No. 17
Constitutional terminology and symbols	Largely removed from the reform text

The Lisbon Treaty preserved much of the institutional substance of the Constitutional Treaty while changing its presentation and legal form. The European Parliament’s historical account describes Lisbon as retaining most of the substantial achievements of the constitutional project, even though the new text was no longer called a constitutional treaty. European Parliament+2

9.4 What was not transferred in the same form?

The Lisbon Treaty did not simply reproduce the Constitutional Treaty with a different title.

It retained the existing treaty architecture rather than replacing it with a single constitutional instrument. The TEU and TFEU remained separate treaties, although they have equal legal value. Euratom also continued to exist under its own treaty framework.

The constitutional symbols were not incorporated into the Lisbon Treaty as binding treaty provisions. The proposed title of Union Minister for Foreign Affairs was replaced by the title High Representative of the Union for Foreign Affairs and Security Policy. The explicit primacy clause was also omitted from the body of the Treaty, although Declaration No. 17 recalled the established case law of the Court of Justice on the primacy of Union law.

The distinction matters. The Lisbon Treaty incorporated many of the earlier project’s reforms, but it did not establish the constitutional order envisaged in 2004. It remained a treaty amending the existing primary law of the Union.

10. The Constitutional Treaty and the Primacy of EU Law

The Constitutional Treaty is particularly relevant to the development of the relationship between Union law and national legal systems.

Its proposed primacy provision sought to express directly in the constitutional text a principle already developed by the Court of Justice. In Costa v ENEL (Case 6/64), the Court had held that the law arising from the European Community could not be overridden by conflicting national legal provisions without undermining the legal order established by the Treaties.

The doctrine was subsequently developed through further judgments, including Internationale Handelsgesellschaft (Case 11/70) and Simmenthal (Case 106/77).

The Constitutional Treaty would have placed the principle in express treaty language. Its failure did not, however, reverse the Court’s case law or remove primacy from the legal structure of the Union.

The Lisbon Treaty omitted the proposed article but included Declaration No. 17 concerning primacy. The declaration referred to the established case law of the Court of Justice and attached an opinion of the Council Legal Service explaining that the omission of an express provision did not alter the existence of the principle.

The legal significance is therefore twofold.

First, the Constitutional Treaty did not create primacy. The doctrine existed before the Convention began its work and had been central to the development of the European Community legal order.

Second, the failure of the Constitutional Treaty did not prevent the continued operation of primacy under the existing legal framework. The principle remains part of the constitutional structure of EU law as developed by the Court of Justice.

This distinction illustrates the difference between the adoption of a new treaty text and the continuity of established legal doctrines.

11. The Constitutional Significance of the Failed Project

11.1 A constitutional project without a constitution

The Constitutional Treaty was an attempt to make the Union’s constitutional character more explicit. It sought to present the Union as a political and legal order founded on common values, democratic institutions, defined competences, and enforceable rights.

Its failure did not mean that the European Union ceased to possess constitutional characteristics. The Court of Justice had long described the founding Community treaties as the constitutional charter of a Community based on the rule of law. The Union’s legal order continued to be structured by principles such as conferral, institutional balance, direct effect, and primacy.

The Constitutional Treaty was therefore an attempted reorganisation and codification of an existing constitutional development, rather than the starting point of constitutionalism in Europe.

11.2 The continuing importance of Member State consent

The ratification crisis demonstrated that major constitutional reform in the European Union remained dependent on the agreement of the Member States.

The Union’s institutions could prepare proposals, negotiate compromises, and approve treaty texts within their respective roles. However, the entry into force of the Constitutional Treaty required ratification by all signatory states.

This requirement reflected the continuing importance of national constitutional processes in the development of the Union. The European legal order was not founded on an autonomous power to adopt a constitution without the consent of its Member States.

The events of 2005 also demonstrated that national consent could not be treated as a purely governmental matter. Where domestic constitutional systems provided for referendums, voters could directly determine whether a proposed treaty would be ratified.

11.3 The tension between integration and national constitutional identity

The Constitutional Treaty brought into focus a continuing question: how far can European integration develop without changing the constitutional identity of the Member States or the character of the Union itself?

Supporters of the project argued that a clearer constitutional framework could make the Union more transparent, democratic, and effective. They considered that the Union’s growing responsibilities required a more coherent institutional structure and a stronger expression of shared values.

Critics raised concerns about the transfer of authority, the possible weakening of national democratic control, the symbolism of a European Constitution, and the direction of economic and political integration.

These positions were not always mutually exclusive. A person could support European cooperation while opposing particular institutional reforms, or favour a stronger Union in some policy areas while resisting greater centralisation in others.

The referendums therefore cannot be understood simply as a contest between supporters and opponents of European integration. They reflected a wider debate about the form, limits, and legitimacy of integration.

11.4 The constitutional influence of the project

Although it never entered into force, the Constitutional Treaty influenced the language and institutional structure of the Lisbon settlement.

It helped consolidate proposals that had been developed during the Convention, including the clarification of competences, the strengthening of national parliamentary scrutiny, the extension of parliamentary law-making, the permanent presidency of the European Council, and the citizens’ initiative.

Its influence also extended to the debate about the Union’s identity. The Lisbon Treaty retained the fundamental values and objectives of the Union, the binding status of the Charter, and a more coherent framework for external representation, while avoiding the constitutional title and several of the more explicit symbols.

The Constitutional Treaty is thus best understood as an unsuccessful treaty in legal terms but an influential stage in the evolution of the Union’s constitutional framework.

12. The Constitutional Treaty in the Current Legal Order

The Constitutional Treaty is not part of the primary law currently in force. It never entered into force and cannot be relied upon as an independent legal basis for action by the EU institutions, Member States, or individuals.

Its provisions did not become binding merely because the Treaty was signed or because a number of Member States completed ratification.

The distinction between signature and entry into force is fundamental in treaty law. Signature authenticates the text and may create certain obligations under international law, including the obligation not to defeat the object and purpose of a treaty before a state has made clear its intention not to become a party, as reflected in Article 18 of the Vienna Convention on the Law of Treaties. It does not, by itself, bring the substantive provisions of a treaty into force.

The Constitutional Treaty therefore has no operative status comparable to the TEU, the TFEU, or the Euratom Treaty.

Nevertheless, it remains a valuable historical and interpretative document. Its text allows scholars and practitioners to examine the reform proposals considered by the Member States, identify the origins of provisions later incorporated into the Lisbon Treaty, and understand the political and constitutional debates that shaped the modern Union.

When examining current EU law, however, the applicable legal provisions must be found in the treaties currently in force, their protocols and annexes, the Charter of Fundamental Rights, and valid secondary legislation, rather than in the unratified Constitutional Treaty.

13. Key Takeaways

• The Treaty establishing a Constitution for Europe was signed in Rome on 29 October 2004 by the representatives of the twenty-five Member States.
• It emerged from the Laeken Declaration of 2001 and the work of the European Convention on the Future of Europe, established in 2002.
• Its principal objective was to simplify the Union’s treaty framework and reorganise its constitutional and institutional structure.
• The proposed Constitution was divided into four parts, covering constitutional principles, fundamental rights, Union policies and functioning, and general and final provisions.
• Major reforms included a single legal personality for the Union, abolition of the pillar structure, a permanent President of the European Council, a Union Minister for Foreign Affairs, a new Council voting system, and an expanded role for the European Parliament.
• It sought to clarify the division of competences between the Union and its Member States and strengthen the role of national parliaments in monitoring subsidiarity.
• The Charter of Fundamental Rights was incorporated as Part II of the proposed Constitution.
• The Treaty was rejected in the French referendum of 29 May 2005 and the Dutch referendum of 1 June 2005.
• Because unanimous ratification was required, the Constitutional Treaty never entered into force.
• The Treaty of Lisbon subsequently incorporated many of its institutional and legal reforms, but through amendments to the existing treaties rather than a single constitutional instrument.
• The Constitutional Treaty is not part of current EU primary law, although it remains an important historical document in the development of the Union’s constitutional framework.

14. Frequently Asked Questions

1. What was the European Constitutional Treaty of 2004?

The Treaty establishing a Constitution for Europe was a proposed treaty designed to reorganise the European Union’s legal and institutional framework. It sought to replace the existing principal treaties with a single constitutional instrument, clarify the Union’s competences, strengthen democratic accountability, incorporate the Charter of Fundamental Rights, and improve the Union’s capacity to act internally and internationally.

2. When was the Constitutional Treaty signed?

It was signed in Rome on 29 October 2004 by representatives of the twenty-five Member States that constituted the European Union at that time. It was published in the Official Journal on 16 December 2004.

3. Why was the Constitutional Treaty rejected?

The Treaty was rejected in national referendums in France on 29 May 2005 and the Netherlands on 1 June 2005. The campaigns involved concerns about national sovereignty, democratic accountability, economic and social policy, the direction of European integration, and the institutional design of the proposed Constitution. The reasons differed among voters and cannot be reduced to a single explanation.

4. Did the Constitutional Treaty create a European state?

No. Although it was called a Constitution and contained provisions resembling those found in national constitutional documents, it remained a treaty requiring ratification by all Member States. It did not establish a sovereign European state or give the Union unrestricted powers. The principle of conferral would have continued to limit the Union’s authority.

5. What would have happened to the European Community under the Constitutional Treaty?

The proposed Constitution would have replaced the European Community with a single European Union possessing express legal personality. The European Atomic Energy Community, Euratom, would have continued to exist separately.

6. Did the Constitutional Treaty introduce the primacy of EU law?

No. The principle of primacy had already been established through the Court of Justice’s case law, particularly Costa v ENEL in 1964. The Constitutional Treaty proposed to state the principle expressly in its text, but its failure did not remove the doctrine from the existing EU legal order.

7. Which reforms of the Constitutional Treaty were retained by the Treaty of Lisbon?

Many institutional reforms were retained, including the Union’s single legal personality, the permanent President of the European Council, the High Representative for Foreign Affairs and Security Policy, the double-majority voting system in the Council, the citizens’ initiative, and the stronger role of the European Parliament and national parliaments. The Charter of Fundamental Rights also acquired binding legal status through the Lisbon reforms.

8. Is the Constitutional Treaty legally binding today?

No. It never entered into force and is not part of the current primary law of the European Union. Its provisions cannot independently serve as legal authority for current EU action. The applicable framework is found in the TEU, the TFEU, the Euratom Treaty, the Charter of Fundamental Rights, and valid Union legislation.

9. What is the difference between the Constitutional Treaty and the Treaty of Lisbon?

The Constitutional Treaty sought to replace the existing principal treaties with a single constitutional instrument. The Treaty of Lisbon instead amended the existing treaties, preserving the distinction between the TEU and the TFEU. It retained many of the proposed institutional reforms but removed much of the constitutional terminology and symbolism.

10. Why is the Constitutional Treaty still important in the study of EU law?

It illustrates the constitutional ambitions of European integration and the limits imposed by the Member States’ ratification requirements. It also provides the historical background to many provisions of the Lisbon Treaty and helps explain the development of the Union’s institutional structure, democratic mechanisms, and constitutional principles.

Conclusion

The Constitutional Treaty of 2004 represents a decisive moment in the constitutional history of European integration. It was an attempt to give the European Union a more coherent legal structure, a clearer institutional identity, and a more explicit statement of its fundamental values and democratic principles. Its proposed reforms addressed genuine difficulties arising from enlargement and the growing complexity of the Union’s activities.

Its rejection in France and the Netherlands demonstrated that institutional reform could not be separated from questions of political legitimacy, national constitutional authority, and public consent. A treaty could be negotiated by governments, debated by European institutions, and approved by many national parliaments, yet still fail if the required ratification process was not completed.

The subsequent Treaty of Lisbon preserved much of the substance of the constitutional project while abandoning its central constitutional form. This outcome did not resolve every debate about the nature of the European Union. Instead, it reaffirmed the distinctive character of the Union as a legal and political order founded on treaties between Member States, operating through common institutions and exercising competences conferred upon it.

The Constitutional Treaty therefore occupies an unusual but important place in EU law. It is a constitution that never became law, a treaty that was signed but never entered into force, and a reform project whose institutional legacy survived the failure of its original legal form. Understanding it helps explain not only how the present European Union developed, but also why its constitutional evolution remains inseparable from the relationship between European institutions, national governments, and the citizens of the Member States.

Official and Further Sources

1. Treaty establishing a Constitution for Europe — Full Text, Official Journal C 310, 16 December 2004. The complete text of the proposed Constitution, including its four parts, protocols, annexes, and final provisions. EUR-Lex

2. Council of the European Union — Treaty establishing a Constitution for Europe. Official treaty record, signature date, publication details, and national ratification information. Consilium

3. European Parliament — Draft Treaty Establishing a Constitution for Europe. Historical overview of the constitutional project and the referendums in France and the Netherlands. europarl.europa.eu

4. European Parliament — The Treaty of Lisbon. An account of the transition from the Constitutional Treaty to the Lisbon reforms and the institutional changes subsequently adopted. European Parliament

5. EUR-Lex — The Treaty of Lisbon. Official summary explaining the Lisbon Treaty, its relationship with the Constitutional Treaty, and the reforms it incorporated. EUR-Lex

6. European Commission — The ABC of EU Law. An accessible explanation of the development of EU law and the constitutional reform process.

7. Council of the European Union — Intergovernmental Conferences. Background on the 2004 and 2007 intergovernmental conferences and the process that led to the Lisbon Treaty. Consilium

8. EUR-Lex — Final Act of the Treaty Establishing a Constitution for Europe. The Final Act and the associated protocols and declarations.