Party (System) Crashers? Success and Failure of Genuinely New Parties in Western Europe (1945-2017)

Over the last years, Western European party systems have experienced increasing electoral instability and the emergence of successful new parties, leading in some contexts to processes of party system de-institutionalization. Yet, notwithstanding the growing relevance of these trends, poor attention has been dedicated to the rise of new parties from a comparative and long-term perspective, while case studies focusing on a single party or country are overwhelming. In this paper we rely on Sikk’s conceptualization of ‘genuinely new parties’, namely parties that ‘are not successors to any previous parliamentary parties, have a novel name and structure, and do not have any important figures from past democratic politics among their major members’ (2005, 399). This concept was originally designed for Central and Eastern European party systems with the purpose of highlighting a clear-cut difference with the insiders of the system (i.e., the founder parties, or their successors). For the first time, we apply this perspective to Western European party systems. By building a dataset covering 20 countries and more than 350 parliamentary elections, we have identified 125 genuinely new parties emerged in Western Europe after 1945. We have tracked the performance of those parties in terms of electoral success, parliamentary representation and government participation. The paper offers evidence of the patterns of success and failure of these party (system) crashers across time, countries, and party families. Furthermore, through a latent trajectory model (Nagin 2005; Mustillo 2009) we provide a classification of such genuinely new parties in terms of their varying ability to enter the system and persist over time, thus becoming part of it.