When Do Mainstream Parties Change Positions? A Set-Theoretic Analysis of Positional Shifts on the Issue of Decentralisation

When parties change tack on any issue, they do so for two reasons: because they must and because they can. Yet the literature on party positional shifts has confounded these two distinct drivers, in part because it relies predominantly on a statistical approach that seeks to identify the causal effect of individual variables without distinguishing their causal proximity to the outcome of positional change. This paper departs from this established method of inquiry to conduct a set-theoretic analysis of the drivers and enablers of party policy shifts on the issue of decentralisation. It uses expert estimates of the position of 282 mainstream parties on the decentralisation issue provided by the Chapel Hill Expert Survey (CHES) to distinguish three outcomes: moves in a pro-decentralist and moves in a pro-centralist direction, and instance of no change in positioning. It then employs a two-step fuzzy-set qualitative comparative analysis (fsQCA) that identifies the configuration of distal drivers and proximate enablers of positional shifts tied to each outcome. The results of this research bears theoretical relevance for understanding what configuration of conditions foster the ‘contagion’ across party systems of new political issues such as Euroscepticism, environmentalism or immigration, engendered by mainstream parties adjusting to the electoral threat of new entrepreneurial parties.