The choice of legal basis of EU legal acts is a constitutional question in EU law, determining the relevant competence, institutional role, voting rule, related procedures, and issues of judicial review. This article advances a legal basis critique of a corpus of EU legal acts adopted in the past decade. As it demonstrates, the legal basis case-law set out by the Court of Justice of the European Union, and the limits of what particular legal bases permit, remain formally undisturbed. The practice of EU law, however, has demonstrably shifted, requiring sustained constitutional attention.