Security, freedom and justice: The limits of mutual trust in EU Criminal law

The tensions between security and justice have shaped integration in the Area of Freedom, Security and Justice (AFSJ) since its early years. This thesis explores how systematic violations of the rule of law and fundamental rights as guarantees of justice limit the fulfilment of security objectives in judicial cooperation in criminal matters. In this area, Member States have resisted supranationalisation and prioritised cooperative instruments based on mutual recognition. Mutual trust provides the constitutional basis to this cooperation, permitting the realisation of security goals based on a presumption of equal compliance with EU values.

Mutual trust is conceived as a constitutional principle that facilitates a multi-level judicial dialogue between Member States’ courts horizontally and, vertically, between them, the European Court of Human Rights (ECtHR), and the Court of Justice of the European Union (CJEU). This thesis demonstrates that this multi-level engagement constitutes the primary governance mechanism to arbitrate tensions between security and justice in criminal matters. Through this judicial dialogue, Member States’ courts identify the areas in which systemic violations of fundamental rights and the rule of law occur. At the same time, the identification of these systemic violations shows the limits of court-based action in criminal matters and clarifies the areas in which further harmonisation remains necessary.

This study argues that the multi-level engagement between courts exposes the limitations of integration based on mutual trust in criminal matters. It demonstrates that meeting the security goals of EU criminal law and guaranteeing that mutual recognition based on mutual trust operates unimpeded requires that the legislature prioritises the harmonisation of fundamental rights and the rule of law. Otherwise, the prevalence of deficient justice standards across the EU will continue to provide reasons to question the absoluteness of mutual trust and, hence, the fulfilment of the security goals of the AFSJ.