Comparing Party System Types at the Regional Level: Czech Regional Elections 2000–2020 as an Example of Vertical Top-down Spill-over

The article aims to contribute to a better understanding of regional-level party politics in post-communist Czech Republic. We follow the multilevel election perspective, which emphasizes that full understanding of regional-level contestation and the resulting shape of regional party systems is only possible when taking horizontal and vertical interactions between regional and other electoral arenas into consideration. By analyzing all regional elections since the establishment of self-governing regions in 2000 to 2020, we found that Czech regional party systems (1) are not converging towards a single type; (2) are not too stable between elections; (3) are characterised by growing fragmentation and the resulting gradual shift from moderate multiparty systems to extreme multiparty systems; and (4) this transformation is largely a result of a top-down form of vertical spill-over as development in the Czech national arena has the main impact on electoral outcomes as well as party system formats at regional level.