Does Ideological Challenger Status Bring Home Party Gains?

Both parties’ and voters’ positions have long been considered structured by the socio-economic left/right dimension. However, significant changes to political life and political systems, caused by a process of globalization have transformed this one-dimensional ideological space. Kriesi et al. (2006) demonstrate how a new, cultural dimension opposes those who gain from open borders, international communication and supranational cooperation, to those who feel threatened by it, and demand the cultural and actual protection of national borders. The subsequent transformation of party systems highly depends on the politicization of new ideological positions by ‘challengers’ of the ideological status quo: new, radical, fringe parties (Van der Eijck & Franklin, 2007; Green-Pederson, 2012; De Vries & Hobolt, 2012). However, this idea also implies that at some point, the ideological ‘mainstream’ is redefined: what once were the issues of the ‘fringes’ will define party competition. In other words, are the yesterday’s challengers today’s mainstream? In order to reply to this question, we investigate to what extent parties that politicized the issue of EU integration have institutionalized by ensuring objective durability in the past 25 years. We make use of the Chapel Hill Expert Survey to identify new, challenger parties and use objective durability as an indicator of institutionalization. This dependent variable includes electoral success, seat share in parliament and executive power. Our intentions are not to explain why, but to describe if and how this process is structurally unfolding in Western democracies in the long term. We argue that the use of random slopes in a mixed regression model is an innovative way to quantitatively approach the long-term development of a relationship that develops across political systems, but that is highly clustered at the level of party systems and therefore can only be adequately described with independent, country-specific regression slopes.