ECJ

The European Court of Justice (ECJ), formally the Court of Justice of the European Union (CJEU) since the Treaty of Lisbon (2009), is the EU's supreme judicial authority. Based in Luxembourg, it was established in 1952 under the Treaty of Paris as the court of the European Coal and Steel Community and evolved alongside European integration. Today it operates under Article 19 of the Treaty on European Union (TEU) and Articles 251–281 of the Treaty on the Functioning of the European Union (TFEU).

The CJEU is composed of two main bodies: the Court of Justice itself, with one judge per member state plus eleven Advocates General, and the General Court, which hears most direct actions from individuals and companies. Judges are appointed by common accord of member-state governments for renewable six-year terms.

Its core functions include:

• Preliminary rulings (Article 267 TFEU): national courts refer questions on EU law interpretation, ensuring uniform application.
• Infringement proceedings brought by the Commission against member states that fail to comply with EU obligations.
• Actions for annulment of EU acts that breach the treaties.
• Appeals on points of law from the General Court.

Several ECJ judgments are foundational to EU constitutional doctrine. Van Gend en Loos (1963) established the direct effect of EU law, allowing individuals to invoke it before national courts. Costa v ENEL (1964) established the primacy of EU law over conflicting national law. Cassis de Dijon (1979) underpinned the mutual recognition principle in the single market. Francovich (1991) created state liability for failure to implement EU directives.

The court has also shaped contemporary policy: the Schrems I (2015) and Schrems II (2020) judgments invalidated EU–US data transfer frameworks, while Achmea (2018) restricted intra-EU investment arbitration. Its rulings are binding on all member states and EU institutions, making it a central actor in European governance.