The application of the EU Charter of Fundamental Rights to the Member States has given rise both to a controversial phraseology and a controversial case-law. This paper offers a reconstruction of the constitutional intent and proposes a conceptualization in conformity with the structural function and the constitutional contemplation of the pouvoir constituent. As to the phraseological debate, it demonstrates that the Charter’s application to the Member States may occur by reason of either “implementation” or “interpretation” of EU law and the two strands are embraced but not synthetized by “scope” as a collective term. As to the substantive debate, it demonstrates that the CJEU’s case-law on “implementation” is not only amorphous but also inconsistent with the Charter’s constitutional mandate. The paper proposes a novel approach based on the notion that the application to the Member States is accessory to the supremacy of EU law. The paper’s argument is presented in the following steps. First, the paper presents the pristine rationale and constitutional function of the application to the Member State through its emergence and historical context. Second, it provides a taxonomy and critical overview of the CJEU’s amorphous case-law and presents the Court’s futile attempt to create a coherent doctrine that faithfully reproduces the constitutional contemplation behind the diagonal application and that reflects the division of competences between the EU and its Member States. Third, it sets out the proposed doctrine of “displacement.”