Le norme cedevoli nel rapporto tra fonti statali e fonti regionali.

My thesis is an analysis of the state power to enact "supplementary" rules with reference to matters reserved to the regions. The first chapter seeks to clarify the theoretical profile of the competence criteria and the actual operation of the jurisdictional relationship between hierarchy and competence. This analysis has required a thorough reinterpretation of three major authors thought’s (Zanobini, Crisafulli and Esposito) who have contributed significantly to the theorization of the competence criteria and relations between normative sources with their works. The second chapter contains a detailed analysis of constitutional jurisprudence in the field of “supplementary” rules. The chapter is divided into three sections and covers the role played by supplementary rules, respectively, in the transitional phases of the constitutional changes, before the reform of Title V of the Constitution and, finally, in the aftermath of the 2001 constitutional reform. My thesis carries out with a brief analysis of Spanish regional system and in particular of the “supletoriedad” clause – in order to make a comparison with an Italian experience. The fourth and final chapter contains the concluding remarks of the work, and focuses on theoretical and practical implications of the institute, with particular reference to the problem of "disapplication" of the law and, finally, the role played by supplementary rules as a sort of supremacy clause.