Institutional design and polarisation. Do consensus democracies fare better in fighting polarisation than majoritarian democracies?

It is often claimed that we are living in an age of increasing polarization. Political views, opinions, and worldviews become increasingly irreconcilable (idea-based polarization), while at the same time society appears to be getting fractured in antagonistic, opposing camps (identity-based polarization). However, a closer look at international datasets reveals that these forms of polarization do not affect all democracies to the same extent. Levels of identity-based and idea-based polarization strongly vary across countries. The question then becomes what can explain these diverging levels of polarization. In this paper, we hypothesize that the institutional design of a country impacts polarization, and that consensus democracies would display lower levels of polarization. Based on a quantitative analysis of the Comparative Political Dataset and Varieties of Democracy data in 36 countries over time (2000–2019), our results show that institutions did matter to a great extent, and in the hypothesized direction. Countries with consensus institutions, and more in particular PR electoral systems, multiparty coalitions, and federalism did exhibit lower levels of both issue-based and identity-based polarization, thereby confirming our expectations. Moreover, we found that consensus democracies tend to be better at coping with identity-based polarization, while the effect on idea-based polarization is smaller.