Polarisation and Party Position Blurring: Evidence from a Cross-Sectional Time-Series Analysis

An extensive literature documents how parties emphasise issue positions strategically in response to voter preferences (e.g. De Sio & Weber, 2014). Surprisingly, relatively few studies consider the effect of voter preferences on the blurring of party issue positions. Of these, just a single study examines the role of voter polarisation on blurring (Han, 2020). In theory, polarising issues offer voters emotionally gripping, straightforward choices, thereby encouraging proximity voting (e.g. Lachat, 2008). As a result, party issue strategies should be particularly sensitive to these issues (Atkinson, 2025), which in some cases leads to clarity / blurring (Han, 2020). However, the literature is missing key longitudinal evidence about this relationship, and the causes of party position blurring more generally (Lefevere, 2024). This gap is crucial because with purely cross-sectional data, it is impossible to rule out the reverse hypothesis – namely, that the clarity of party issue positions leads to voter polarisation (Freeder et al., 2019; Moral & Best, 2023). In relation to this, it remains difficult to separate the effect of voter polarisation from party polarisation. In theory, one party’s decision to take a more extreme position may clarify both their and their opponents’ issue positions (Galindo-Silva, 2024). To further unpack the relationship between polarisation and blurring, I propose a time series analysis that combines data about voter polarisation and party position blurring across several issues and party systems, predominately drawing on data from the European Social Study and the Chapel-Hill Expert Survey (e.g. Ibenskas & Polk, 2024). References – Atkinson, W. J. (2025). The two faces of issue polarisation and their impact on party competition in Western Europe. Party Politics, 13540688251405734. De Sio, L., & Weber, T. (2014). Issue yield: A model of party strategy in multidimensional space. American Political Science Review, 108(4), 870–885. Freeder, S., Lenz, G. S., & Turney, S. (2019). The importance of knowing “what goes with what”: Reinterpreting the evidence on policy attitude stability. The Journal of Politics, 81(1), 274–290. Galindo-Silva, H. (2024). Ideological ambiguity and political spectrum. Economics of Governance, 25(2), 139–180. Han, K. J. (2020). Beclouding party position as an electoral strategy: Voter polarization, issue priority and position blurring. British Journal of Political Science, 50(2), 653–675. Ibenskas, R., & Polk, J. (2024). Party responsiveness to public opinion in a multi-dimensional policy space. Journal of European Public Policy, 1–28. Lachat, R. (2008). The impact of party polarization on ideological voting. Electoral Studies, 27(4), 687–698. Lefevere, J. (2024). Is there clarity in ambiguity? A literature review of party positional ambiguity. Party Politics, 30(2), 334–344. Moral, M., & Best, R. E. (2023). On the relationship between party polarization and citizen polarization. Party Politics, 29(2), 229–247.