Cost of change: How have changing government alliances between parties affected polarization and the rise of radical parties?

Western European politics has become more polarized and revolved around growing hostility and incivility along partisan lines. Existing research has elaborated on the recent polarized phenomena by illustrating that the success of radical parties has potentially increased the degree of polarization, both ideological and affective ones. Because of that, scholars tend to treat and perceive the increasing polarisation as a response to the rise of radical parties, especially right-wing parties. I argue that the rise of radical parties may not be a direct effect of the increasing polarization. Rather, the success of radical parties may mediate the relationship between changing government alliances between parties and polarization. The literature on radial parties has pointed out that the government coalition formed between the left Socialist and the right Conservative parties opens up space for the rise of radical parties. In Germany, the rise of the far-right AfD was followed by the coalition government formed between the Conservative CDU and the Socialist SPD. This also occurs in Austria where the Austrian far-right FPÖ received the highest vote share in 2017 after the 2013-2017 coalition government between the Socialist SPÖ and the Conservative ÖVP. This article delves into how changing government alliances between parties and the characteristics of change affect the degree of affective and ideological polarization. The latter are prone to influence the rise of radical parties. This research design focuses on disentangling the relationship between changing government alliances between parties, the rise of radical parties, and the degree of affective and ideological polarisation. To do so, I examine testable hypotheses by using panel data set on 83 elections from 14 Western European countries between 1998 and 2019. The degree of two types of polarization is measured based on the post-election survey data on the self-placement of citizens on parties’ left-right ideology and the like-dislike of a partisan in-outgroup from the Comparative Study of Electoral Systems (CSES) studies. The information on the changing form of government alliances between parties relies on the data from the Parliaments and Governments (ParlGov) database. Empirical results show that the greater left-right ideology distances between parties of changing government alliances in the multi-party coalition government are associated with the higher degree of the two types of polarization. The intensification of effects varies across the size and characteristics of parties. The answer to this question has implications for understanding how party competition between party elites in a governmental arena polarizes voters in today's Western European democracies.