The Member States 7 February 1992, Consolidated version of the Treaty on European Union - TITLE I COMMON PROVISIONS - Article 4

Also known as

Article 4 of the Treaty on European Union (TEU), as consolidated, establishes the foundational allocation of competences between the Union and Member States, providing that competences not conferred upon the Union remain with the Member States. The provision mandates that the Union respect Member States' equality before the Treaties, their national identities rooted in fundamental political and constitutional structures including regional and local self-government, and their essential State functions—expressly reserving national security as the sole responsibility of each Member State. Under the principle of sincere cooperation (principe de coopération sincère), both the Union and Member States are obliged to assist each other in fulfilling Treaty obligations, with Member States required to take all appropriate measures to ensure compliance and to refrain from any action that could jeopardise the attainment of the Union's objectives.AI