The EU Constitutional Treaty of 2004: What It Was

The Treaty establishing a Constitution for Europe, usually called the EU Constitutional Treaty, was signed in Rome on 29 October 2004 by the then 25 member states of the European Union. It was meant to replace the existing founding treaties with a single, more readable text and to reform the institutions of an enlarged Union. It never entered into force: after voters in France and the Netherlands rejected it in referendums in 2005, ratification stopped. Much of its content was later carried over into the Treaty of Lisbon.

This page summarises what the treaty contained, how ratification unfolded and what happened afterwards. It reports events and does not take a position on the treaty.

How the treaty came about

• 2001: EU leaders agreed to prepare a fundamental reform and set up a convention for that purpose.
• 2002–2003: a European Convention made up of representatives of national governments, national parliaments, the European Parliament and the Commission drafted a text in public sessions.
• 2003–2004: an intergovernmental conference of the member states negotiated the final version.
• 29 October 2004: signature in Rome.

The convention method, with parliamentarians at the table and public debates, was new for EU treaty-making at the time.

What the treaty contained

Area	Main provisions
Structure	One treaty replacing the earlier ones; the EU would have a single legal personality
Fundamental rights	The Charter of Fundamental Rights incorporated into the text
Institutions	A permanent President of the European Council; a Union Minister for Foreign Affairs
Voting in the Council	Qualified majority as a double majority of member states and population
Competences	A clearer list of what the EU and the member states may decide
Participation	A citizens’ initiative; a stronger role for national parliaments
Membership	An explicit procedure for leaving the Union
Symbols	Flag, anthem, motto and Europe Day named in the treaty

The voting rule is explained on double majority; the citizens’ initiative later became the European Citizens’ Initiative.

Ratification and the referendums of 2005

Like every EU treaty, the Constitutional Treaty needed ratification by all member states. Most planned to ratify in parliament; several decided to hold referendums.

Date (2005)	Country	Type	Outcome
20 February	Spain	Consultative referendum	Yes
29 May	France	Referendum	No
1 June	Netherlands	Consultative referendum	No
10 July	Luxembourg	Referendum	Yes

By the time ratification came to a halt, 18 member states had ratified the treaty, two of them by referendum. After the French and Dutch votes, the European Council in June 2005 declared a period of reflection. Several countries that had announced referendums postponed them.

A wider list of votes on European integration is on EU treaty referendums.

Why it failed: the explanations offered

Because a treaty needs unanimous ratification, two No votes were enough to stop it. Why those votes went the way they did has been studied extensively. Explanations put forward in post-referendum surveys and research include:

• concerns about economic and social issues and about recent enlargement;
• dissatisfaction with national governments at the time of the vote;
• the length and complexity of the text and a perceived lack of information;
• different views on the direction and pace of European integration.

Researchers weigh these factors differently, and they differ between France and the Netherlands. We list them only as reported explanations, not as an assessment.

From the Constitutional Treaty to Lisbon

After the period of reflection, member states agreed in 2007 to abandon the idea of a single constitutional text and instead amend the existing treaties. The result was the Treaty of Lisbon, signed on 13 December 2007 and in force since 1 December 2009.

Constitutional Treaty	Treaty of Lisbon
Replaces the existing treaties	Amends the existing treaties
‘Constitution’ in the title	No constitutional terminology
Union Minister for Foreign Affairs	High Representative of the Union for Foreign Affairs and Security Policy
Charter of Fundamental Rights in the text	Charter legally binding by reference
Symbols named in the treaty	Symbols not mentioned in the treaties
Double-majority voting	Double-majority voting, applied from 2014

Lisbon itself was rejected in an Irish referendum in 2008 and approved in a second Irish vote in 2009. The consolidated treaties are available on EUR-Lex.

Why the episode still matters

The 2005 votes are often cited in debates about how EU treaties should be ratified and whether citizens should be asked directly. Some see them as a democratic correction, others as a sign that complex treaties are poorly suited to yes/no votes. Both readings are part of the debate. For the general mechanics of referendums, see What is a referendum? and the country overview.