This article offers a reconstruction and assessment of the emerging rebellion of European constitutional courts against the exceptionless supremacy of European Union (EU) law. It presents the ontological theories of supremacy and how the Court of Justice of the EU (CJEU) overcame the first two major challenges of its history: the existential challenge of canonizing the general doctrine of supremacy and the Solange challenge of national fundamental rights. It provides an account of the emerging ultra vires challenge, including its root cause and evolvement, and provides an assessment and sets out proposals. The article demonstrates that the crux of the matter is not the primacy of EU law but the interpretive primacy of the CJEU. It argues that the rebellion was triggered by the perception that the CJEU case law features a declining normative and an increasing policy character. The debate about the CJEU's evolutionary interpretation, in a certain sense, parallels US constitutional law's debate between originalism and the living constitution, with the difference that the EU is a pluralist legal order.