tory convention ( suggested by Parliament ) composed of members of the European Parliament , national parliaments and national governments , prepared the reforms . These were codified in a new constitution which would have replaced the existing treaties , but which fell when France and the Netherlands rejected it . That led to a decision to keep the existing treaties but amend them through what became the Lisbon Treaty , which took up the bulk of the proposed reforms . The convention method is now laid down in the Lisbon Treaty for future revisions , except where Parliament agrees that it is not necessary .
Each one of these treaties extended the EU ’ s areas of competence , enlarged the area in which the Council can act by QMV , and extended the powers of Parliament . Each one was only a partial reform . But cumulatively , they transformed the European Community as it was before 1987 into the Union that we know today .
Parliament ’ s legislative powers were increased step by step . The SEA tentatively brought in the cooperation procedure . This was supplemented with the codecision procedure in the Maastricht Treaty , before being replaced by the codecision procedure in the Amsterdam Treaty . Codecision was itself revised in Parliament ’ s favour by the Amsterdam Treaty and extended in scope in the Amsterdam , Nice and Lisbon Treaties , until it became the ordinary legislative procedure , applicable to the bulk of EU legislation , and requiring the agreement of both Parliament and the Council for legislation to be adopted , with up to three readings in each institution . The consent procedure , initially envisaged only for the occasional cases of accession of new Member States and association agreements , was gradually extended to cover all significant international agreements and some specific types of legislation . Since Lisbon , any delegation of powers to the Commission to adopt delegated acts must be approved by Parliament and can be repealed by
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