1. The system of constitutional guarantees introduced by the Italian Constitution and by the laws, constitutional and ordinary,' by which it is implemented, consists primarily in the establishment of a Court with exclusive jurisdiction to determine the conformity of legislation to the Constitution. The Court is empowered to pass upon the constitutional legality of statutes and to declare their inefficacy erga omnes; its judgment is not subject to review of any kind.2 In inspiring motive, if not in technical details, such a system can be traced back to a renowned ancient doctrine, which began to form itself almost at the