Traditionally studies on the causes and origins of regionalist party electoral strength have focused on sociological and historical specificities of the regions. Following part of the most recent scholarship, this paper aims to place the lens on the institutional environment in which these parties compete, investigating the impact of the degree of regional authority (distinguishing between shared-rule and self-rule, and between ordinary or special authority) and the spill-over effects between different electoral arenas (regional towards national and vice versa). Our analysis is based on a novel dataset of 136 regionalist parties across 320 regions and 18 countries. As far as the impact of regional authority is concerned, we advance a preliminary and very tentative interpretation of the findings which leads us to conclude that the causal relationship works predominantly in the other way around: it is regionalist parties’ strength that affects the level of regional authority, rather than vice versa.
