This document discusses the role of the European Court of Justice in the third pillar of EU law regarding police and judicial cooperation in criminal matters. It outlines what the EU treaties say about the Court's competences in this area and how the Court has interpreted its own role. The document also examines the Court's contributions, such as restoring the consistency of the legal system and mutual recognition between member states. However, it notes some drawbacks of the Court's interventions, such as suboptimal legal solutions and reversals of communitarization. Overall, the document evaluates that the Court's involvement came politically too early but was necessary given the specificity of decisions taken in justice and home affairs.