Between Discretion and Proportionality: The Duty of Care in EU Judicial Review

This article concentrates on the ‘duty of care’ or ‘diligence’, a principle that has become ubiquitous in CJEU case law due to its central role in calibrating the intensity of judicial review of EU acts on the legislative, regulatory and single-case decision-making levels. This article explores the development of the principle and critically reviews its use as well as whether it actually achieves the demands placed on it. The article further examines the tools developed and the emergence of the duty of care as a principle conferring individual rights in various procedural contexts. The article describes how the duty of care has become a central link between on the one hand, a separation of powers-inspired respect for discretion of the institutions and bodies of the EU and, on the other hand, ensuring a rule of law based effective review of the legality of acts – a central feature in the EU specific approach to developing proportionality.