The Intergovernmental Conference began with the aim of adopting the European Constitutional Treaty drafted by the Convention on the Future of Europe. The six founding countries of Europe (Germany, Belgium, France, Italy, Luxembourg, Netherlands), with the support of Great Britain, are in favor of the Constitutional Treaty. However, Poland and Spain oppose it, while the new countries that joined the EU express significant reservations. The priority for each of the “small” countries is to maintain “their own” representative in the European Commission, while the Convention provided for limiting their number to 15. On the same day, an extraordinary European Council meeting was held.
The Treaty establishing a Constitution for Europe was approved by the European Council on 18 June 2004 and signed in Rome at the end of the same year in the presence of the President of the European Parliament, Josep Borrell Fontelles. While it had been approved by the European Parliament (Méndez de Vigo-Leinen report), the Treaty was subsequently rejected by France (29 May 2005) and the Netherlands (1 June 2005) in their respective national referendums.
After the rejection of the Constitutional Treaty, member states began the process of drafting the Treaty of Lisbon.