Regions and local governments play a very important role in the application of European law and in the implementation of European policies. The economic crisis of 2008 has accentuated territorial and social differentiation and highlighted the negative effects of globalization. This circumstance has created resentment among peripheral and marginal communities in the electoral results, but also a strong request for involvement, participation and sometimes independence from territories. These developments raise new questions about the relationship between the EU and the Regions and, more widely, about the role of subnational entities in the EU integration process, as they are the institutions nearest to citizens.
The aim of this article is to contribute to that debate by exploring the following research question: ‘is subnational differentiation positive or negative for European integration?’ Towards a possible answer, two perspectives are examined from a constitutional law approach. From the top down, it examines the attitude of the EU towards regional differentiation, from the origins of the EU integration process and its development until recent initiatives and proposals. From the bottom up, it analyses the role of subnational entities by presenting the Italian experience, through the reforms that have been approved over the years until the recent proposal for asymmetric regionalism. The aim is to understand whether regional differentiation still represents a positive element for the European integration process, considering the role that subnational entities play in many policies and the challenges described earlier.