EU Member States may have recourse to ‘upstream’ national judicial protection under the German Civil Procedure Code to declare inadmissible and thereby preclude intra-EU investment arbitration proceedings brought under the auspices of the International Centre for Settlement of Investment Disputes (ICSID) Convention. That remarkable conclusion by the Bundesgerichtshof (German Federal Court of Justice) constitutes the first attempt of a higher court of an EU Member State to render compatible the seemingly contradictory obligations on national courts arising from EU law and the ICSID Convention. However, even more important than the court’s conformity assessment are the inherent consequences of its conclusion: the incompatibility of the ICSID Convention with EU law and the obligation, on all EU Member States and their institutions, to disapply that convention in intra-EU investment arbitration matters and ultimately to denounce it collectively.