After having outlined some of the legal implications, as well as some of the main issues raised by the accession of the EU to the ECHR, the paper focuses on the prior involvement mechanism as to situations when the alleged violation involves national judicial proceedings. It seeks to demonstrate that the mechanism does match both the ECHR's features, and the precise conditions imposed by EU primary law on the accession process. It further argues that the prior involvement rule does not require a revision of the EU Treaties. Finally, it is argued that the ECJ's prior involvement mechanism encourages the positive intervention of the ECJ, while recognizing the subsidiary external control of the Strasbourg Court. It seeks to preserve the primary role of both Courts in their respective domains, on the assumption that the protection of human rights requires the two Courts to be not rivals for primacy, but rather complementary partners for progressiveevolution in the interest of improving individual protection. This is, in the author's view, the fundamental rationale for the prior involvement mechanism.