The Requirement of Unity in EU International Representation: A Principle, an Objective or Nothing at All?

This contribution examines the concept of unity in EU international representation and assesses whether it constitutes a principle, an objective, or remains a general aspiration in EU external relations law. The requirement of unity in international representation, while not explicitly mentioned in the Treaties, has emerged through CJEU case law in connection with the sincere cooperation principle under Article 4(3) TEU. The contribution traces the ambivalent and inconsistent application of this concept from its origins in Ruling 1/78 through the subsequent jurisdiction, revealing that the Court has not used it consistently, exceptionally characterising it as a self-standing principle, other times it appears as an objective to be achieved through the sincere cooperation and consistency principles. The contribution proceeds in two main parts. First, it assesses the vertical dimension of unity in international representation between the EU and Member States, examining how this requirement has evolved from an 'accidental principle' closely tied to mixed agreements and shared competences and evolving to a more developed concept linked to coherence and effectiveness in EU external action. Second, the article addresses whether unity in international representation could be exported to apply horizontally between EU institutions to bridge the fragmentation in external representation. Drawing on Advocate Opinion in the MoU Switzerland case, it examines whether the requirement of unity in international representation could infuse more coherence into the fragmented external representation system involving the Commission, Council, High Representative, and other global actors. The article ultimately questions whether unity in international representation can serve as a guidance for the application of sincere cooperation and consistency on the horizontal level under the condition of assigning precise powers to EU institutional actors.