Demystifying Autonomy: Tracing the International Law Origins of the EU Principle of Autonomy

CJEU case law has long emphasized the autonomy of the EU legal order, recently triggering the foreclosure of intra-EU investment arbitration. Though academic discourse has treated this as a European peculiarity, autonomy is not unfamiliar to international law as an inherent attribute of all international organizations (IOs). This Article traces how the CJEU employed this as the basis for the development of a legal principle of significant constitutional role in safeguarding the EU's jurisdictional integrity. First, It considers the EU conception of autonomy on the basis of two identified dimensions of IOs' autonomy under international law. Political autonomy characterizes the scope of an IO's powers and its independent legal personality. Institutional autonomy denotes its (im)permeability to external norms. Second, the Article examines autonomy's different normative status under international and EU law as a legal notion and a constitutional principle, respectively. Rather than viewing the latter as an EU invention, it amounts to a Pygmalian judicial creation-the CJEU drew inspiration from a notion of international law and adapted it within the Union framework. The Article justifies these adaptations by reference to international law in light of the EU's institutional-judicial architecture and the intertwining of autonomy with, inter alia, Article 2 TEU values.