Sincere cooperation

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In European Union law, sincere cooperation (Article 4(3) TEU) is one of the foundational principles of the European Union, which determines that the Union and the Member States are required to implement any necessary measures to guarantee compliance with the duties stemming from the Treaties "in full mutual respect".^[1][2]

Sincere cooperation is mentioned explicitly not only in the Treaty on European Union but also in the Court of Justice of the EU's case law, applicable to different exclusive, shared, supporting competences, such as the environment, the Area of Freedom, Security, and Justice, public health, competition rules governing the internal market, and others.^[3][4][5]

The jurisprudence of the CJEU has elaborated on four main responsibilities that derive from the principle of sincere cooperation:^[1]

1) An obligation for respect and assistance between the EU and Member States in attaining the Treaties' objectives

2) Member States have an active obligation to cooperate and comply with original and derivative European law

3) Member States need to refrain from taking any measures that would impede the aims and goals of the Union

4) Member States should facilitate the institutions of the EU to accomplish the Union's objectives.