Comparing electoral competition at the subnational level: vertical and horizontal spill-over in Czech and Poland regional elections and their impact on multilevel democracy

Electoral competition is one of the basic indicators of the quality of democracy, as free party competition or contestation is one of the fundamental conditions of democracy. This is reflected in Dahl’s (1971) dimension of liberalization, which refers to the extent to which political opposition is able to compete for power. Therefore, as long as the party system is viewed as a system of interactions arising from interparty competition (Sartori 1976), the quality of those interactions represents the central focus of quality of subnational democracy in the dimension of competition. The present paper aims to contribute to a better understanding of regional-level party politics in post-communist Czech Republic and Poland. We follow the multilevel election perspective, which emphasizes that full understanding of regional-level electoral competition 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 (Golder et al. 2017), i.e., the effects of vertical spill-over between the national and regional arenas as well as horizontal spill-over between various regional arenas (Schakel and Romanova 2021). We analyse data on electoral competition in all regional elections from the establishment of self-governing regions in Poland (1998) and the Czech Republic (2000) to the last regional elections in 2018 (Poland) or 2020 (the Czech Republic) in 14 Czech regions (kraje) and 16 Polish voivodships (województwa) and compare type of the party competition at the regional level against the form of party competition at the national level in a long-term comparison. The main goal of the paper is to examine especially three main research questions: What types of party systems have emerged in the Czech and Poland regions? How stable are they? Is it possible to identify some form of vertical spill-over between national and regional party systems (vertical spill-over) or does the development in one or more regional arenas impact on the shape of party systems in other regional arenas (horizontal spill-over)?