The assent procedure was introduced by the Single European Act.
It requires the Council to obtain Parliament's assent before certain important decisions are taken. The European Parliament may accept or reject a proposal but cannot amend it. If the European Parliament does not give its assent, the act in question cannot be adopted.
The assent procedure mainly applies to the accession of new Member States (Article 49 of the EU Treaty), association agreements and other fundamental agreements with third countries (Article 300 of the EC Treaty), and the appointment of the President of the Commission.
It is also required with regard to citizenship issues, the specific tasks of the European Central Bank (ECB), amendments to the Statutes of the European System of Central Banks and the ECB, the Structural and Cohesion Funds, and the uniform procedure for elections to the European Parliament.
Since entry into force of the Treaty of Amsterdam, the Parliament's assent has also been required for sanctions imposed on a Member State for a serious and persistent breach of fundamental rights under the new Article 7 of the EU Treaty. The Treaty of Nice has made the Parliament's assent mandatory where reinforced cooperation between certain Member States is envisaged in an area which is subject to the codecision procedure.
The European Convention established by the Laeken Declaration in December 2001 has been asked to propose simplifications to the procedures for the adoption of the various types of Community act and is therefore considering the future use of the assent procedure.
See:
Codecision procedure
Consultation procedure
Council of the European Union
European Commission
European Parliament