Understanding the Complexity of Party Instability in Parliaments
P11-4
Presented by: Sona Golder, Raimondas Ibenskas, Allan Sikk
How do parliamentary party switches affect party systems? We analyse the patterns of party switching in eight democracies (Estonia, Ireland, Italy, Lithuania, Norway, the Netherlands, Poland and Romania) from the early 1990s to early 2020s. We measure the switches along multiple dimensions. First, we consider the magnitude (the number of MPs involved), the coordination of moves (individual vs. collective switching) and the sequencing of switches (simultaneous or staggered). Second, we take account of the origin of switchers: unaffiliated MPs, from one or several parliamentary groups, and combinations thereof. Third, we consider the destination of switchers: non-affiliated status, an existing or new parliamentary group, and combinations thereof. Our approach sheds new light on the complexity of party instability. Elucidating these types of party instability allows us to examine conditions under which we see actors engaging in one type versus another. For example, when are we likely to see “collective defection” (coordinated switches from one parliamentary group to another), “fission-fusion” (coordinated moves from several groups to form a new parliamentary group) or “exit” (MPs exiting their parliamentary group to become independent MPs)? Examining a broader set of possible types of instability will allow us to provide a more complete picture of parliamentary party instability than is provided in the current literature. The motivations for party switching, and the type of party switching that occurs, have consequences for party support and thus affect party systems generally.