Revision of the Treaties
Prior to the Treaty of Lisbon’s entry into force in 2009, there was only one procedure for the revision of the treaties on which the EU is based: the convening of an intergovernmental conference. Since 2009, Article 48 of the Treaty on European Union has laid down two procedures for the revision of the treaties.
Ordinary revision: this relates to key changes in relation to the competences of the EU and requires the convening of an intergovernmental conference to adopt proposals for amendments by consensus. All EU countries have to ratify the treaty amendments for them to enter into force.
Simplified revision: where the proposed amendments relate to the EU's policies and its internal actions, the European Council unanimously adopts a decision on the amendments having consulted the Commission, the Parliament and the European Central Bank (if the amendment concerns monetary matters). The new treaty provisions only enter into force following their ratification by all EU countries according to their own constitutional procedures.