Is disloyalty rewarded? The electoral consequences of bloc changes of Scandinavian Centre Parties 1977–2019

AbstractCentre Parties (Agrarians, Christian Democrats and Liberals) used to be an established part of the Scandinavian party systems and have often been pivotal for government formation. With ongoing individualisation, secularisation, decline of traditional cleavages, and the rise of new ones such as immigration, as well as polarisation, these parties face the challenge of losing representation in parliament as already happened to the Danish Centre Democrats and Christian Democrats. To shift a party's bloc affiliation and coalition preferences is a feature of centre parties, and it may itself be a strategic decision to mobilise new voters in a changed political environment to survive. Yet, it may alienate voters. While the strategic decision to change bloc is common among Scandinavian centre parties and theoretically relevant, empirical investigations of the electoral effects of bloc changes have been dim. We provide a systematic analysis of the electoral effects of bloc changes in Scandinavia in the last four decades. We collected data on bloc changes of Scandinavian centre parties and found 24 between 1977 and 2021. Our panel regressions reveal that bloc changes are indeed electorally costly as centre parties on average lose around 2% after a bloc change. Frequent bloc changes in the past do also reduce a party's average electoral performance. The electoral punishment of a bloc change, however, is cushioned by a large membership base as centre parties evade significant losses if they have a strong anchor in the electorate.