Case Note: A Tale of a Few Cities: When International Legal Orders Collide: The UK Supreme Court decision in Micula

The CJEU’s decision in Commission v. United Kingdom (C-516/22), ruling that the UK Supreme Court’s (UKSC) judgment in Micula v. Romania violated EU law, has revived the debate on whether multilateral treaty obligations are erga omnes partes (owed to all Contracting Parties) or if, after a breach, rights are owed only to the injured state. The UKSC in Micula held that the obligation to enforce an ICSID award under Article 54 of the ICSID Convention applied universally to all Contracting States. In contrast, the CJEU rejected this interpretation, arguing that only the beneficiary’s home State holds the right of enforcement, while other States have a ‘purely factual interest.’ These rulings reflect a broader unresolved debate in international law, which stems from the ICJ’s Barcelona Traction case. However, neither court engaged with this scholarship in any detail, meaning both decisions are surprisingly unreasoned on such a significant question. This can be considered a missed opportunity for the development of treaty law, particularly where multilateralism has featured heavily in recent decades.