Subsidiarity, proportionality and the role of the national parliaments in the European legislative process

Since the entry into force of the Lisbon Treaty (2009), the EU national parliaments have had the right to control the principle of subsidiarity through the Early Warning System (EWS). This study, commissioned by the European Parliament's Policy Department for Justice, Civil Liberties and Institutional Affairs at the request of the AFCO Committee, examines how the EWS has worked over the past 15 years. It also looks into the interaction of Parliament, the European Commission, local and regional entities, the Committee of the Regions, the Court of Justice of the EU and the Council with national parliaments to this end. Moreover, it considers the principle of proportionality and the EU institutions' relationship with it.