The multilevel electoral system and the success of new political parties

Recently, party systems across Western Europe have become highly fragmented. One of the drivers of fragmentation is the electoral success of new parties. One explanation for the success of new parties is the recent decentralisation trend and the emergence of multilevel electoral systems. As new parties can distinguish themselves in the regional electoral arena from established parties by mobilising voters on issues that are salient in a particular region. Once parties have shown that they are viable alternatives in regional elections, they can also try their luck in national elections. Meanwhile, parties that first win a seat in the national elections can use regional elections to consolidate their position. Studies have shown that decentralisation leads to the establishment of new parties (e.g., Thorlakson, 2009; Massetti & Schakel, 2017), and that the chances of survival of new parties are higher when there is a strong regional tier (Bolleyer, 2013). However, the literature pays surprisingly little attention to how multilevel level electoral system (i.e., the electoral rules that conduct the timing of regional and national elections and the translation of votes into seats into regional and national parliaments) affects the electoral success of new parties. In this paper we argue that the extent to which the regional electoral arena affects the national electoral arena is dependent on the multilevel electoral system. We expect that new parties are more successful in regional elections when it easier to win a seat in regional parliament. New parties also thrive when regional elections are second-order elections. The extent to which regional elections are second-order is highly dependent on the timing of regional election vis-a-vis local, other regional, and national elections. At the same time, we also expect that new parties are more successful in regional elections if regional authority is high. As parties then can mobilise voters based on regional issues. However, the extent to which new parties can extend this success in national elections depends on how easy it to win a seat in national parliament in that region relative to winning a seat in regional parliament. We test our hypotheses utilising a dataset that includes 49.715 party observations of parties that competed in national and/or regional elections in 296 national elections and 3.307 regional elections that are held in 282 regions in 15 Western European countries. We find that the multilevel electoral system has a strong impact on new party success in both regional and national elections in addition to the impact of regional authority.