Assimilation, contrast and voter projections of parties in left-right space

Abstract

When voters place parties in their system along the left-right dimension, they often pull their preferred party closer towards them (assimilation) and push the opposition further away (contrast). This article asks a simple question: are such assimilation and contrast effects similarly powerful across different types of electoral system? I hypothesize that systems employing single-member districts will tend to strengthen assimilation and contrast because they mechanically reduce the number of parties, while shifting the focus of electoral competition away from the party and towards the candidate. Using data from 18 advanced democracies compiled by the Comparative Study of Electoral Systems and hierarchical modelling I find that contrast effects are indeed stronger in majoritarian systems, while assimilation effects appear similarly strong regardless of the institutional setting. These findings suggest that institutional design holds lasting consequences for how we perceive politics and, perhaps also, for our ability to effectuate democracy.