This would be comparable in effect to a reservation by a party state to the ECHR which requires that the interpretation of ECHR rights by the ECtHR must not go further than the national interpretation of fundamental rights. This appears to be extremely difficult to reconcile with the very object and purpose of the ECHR.
Second, the CJEU does not address at all Art. 52 (3) of the Charter according to which the rights granted in the Charter of Fundamental Rights which correspond to rights granted under the ECHR have the same content and scope as the latter. The ECHR operates thus as a source of knowledge on the minimum standard of protection of such fundamental rights which form part of EU primary law. There is, as a consequence, already a mechanism in EU law which reconciles the scope and content of fundamental rights in the Charter and the ECHR to a considerable extent. For most EU fundamental rights, the jurisprudence of the ECtHR is thus already relevant and binding. Within the scope of application of EU law national courts can already now apply higher standards of fundamental rights protection based on the ECHR and are obliged in cases of doubt to submit a question to the CJEU in the framework of a preliminary reference procedure. This again ensures that the Court has the last word on the standard of protection applicable in EU law.