In the work of the Italian Constituent Assembly, the decision to establish a regional level of government served to achieve a dual purpose: to create a more efficient and impartial administration, and to facilitate citizens’ democratic participation in the life of public institutions. The distribution of legislative power and administrative functions between the central State and the Regions should have been instrumental in this project. However, the fulfilment of this desire did not entirely align with expectations. This article aims to identify the reasons for these developments, highlighting the various phases of the Italian regionalization process on a diachronic level and analyzing the interpretations provided by the Constitutional Court to affirm a principle of loyal collaboration between the State and the Regions. Finally, based on these investigations, some proposals are formulated to test a new relationship model between the different levels of government.