Abstract The association between social sorting and political polarization is increasingly evident. Often overlooked is, however, the role of spatial sorting. In line with the US evidence, we can expect internal homogenization and external differentiation of neighbourhoods in their voting behaviour, also in the European context. In this article, we conduct the first longitudinal analysis of such spatial polarization in a European multi-party system, exploring its degree and development across several spatial scales, innovatively employing multi-group statistical indices developed for the study of ethnic segregation. We analyse the case of Czechia, contributing to a scarce amount of political polarization evidence in this country. The resulting spatial polarization of voting is generally very low, with the trajectory in the shape of the letter “V,” corresponding to three phases of Czech party politics. The 2002 legislative election saw the greatest degree of internal electoral heterogeneity of neighbourhoods, preceded by the period of formation of Czech party politics and followed by the period of increasing prominence of populist/anti-populist and cultural cleavages. Despite the increase in spatial polarization in recent years, Czech electoral behaviour still remains more or less evenly distributed in space, and the Czech mass political polarization should be rather attributed to factors other than neighbourhood homogenization.
Cihlář et al. (Wed,) studied this question.