From 2001 to 2004, he was President of the Convention on the Future of Europe. On 29 October 2004, the European heads of state approved and signed the European Constitution based on a draft supported by Giscard d'Estaing's work at the Convention. Although the constitution was not approved by French voters in May 2005, Giscard d'Estaing continued to support for its passage in other European Union states. 