Sustainable Development: A Principle of EU External Relations Law?

The contested concept of sustainable development is ubiquitous in EU law, including in EU external relations law. Its legal status as a principle, however, lacks clarity, much like in international law. Sustainable development is prescribed as an aim to be pursued in the EU’s relations with the wider world both under Article 3(5) and 21 TEU. It has acquired particular prominence in the fields of EU external action traditionally associated with this concept, such as trade policy, development cooperation and environmental action, although its application varies across each of these fields. The use of sustainable development, however, is not confined to these domains only, and it often features in relation to other areas of EU external relations. Within this context, this article questions whether sustainable development could possibly be considered a separate principle of EU external relations law. For this purpose, it traces the position and origins of this concept in the EU constitutional framework. Most importantly, the article analyses the manifestations of this concept in the key fields of external action mentioned above, namely trade policy, development cooperation, and environmental policy. In this connection, it critically examines the relevant case law of the Court of Justice of the EU for any hints on the nature of this concept. Ultimately, the paper argues that sustainable development is not a principle of EU external relations law, but it is inherently linked to other principles, such as coherence and principle of integration.