In this essay,\~Bonfreschi and Maccaferri\~consider the concept of regionalismfrom a subnationalperspective rather than an internationalone, discussing the problem of how states deal with regions or smaller unities within the state. From this perspective regionalismis a notoriously imprecise term-used to describe everything from decentralization of political power via \~economic restructuring to the mobilization of subnational identities-but it is undeniable that starting from the 1960s western Europe has experienced a true and proper re-emergence of territorial cleavage.