This article examines changes in the electoral relevance of traditional social cleavage groups in eight West European democracies, where electoral relevance is defined as group contributions to party vote shares. The approach presented here demonstrates the critical importance of both the electoral behaviour and the size of the cleavage group when electoral outcomes are of interest. The findings from analyses of the behaviour and size of working class and religious citizens (1975–2002) reveal significant declines in the contributions of these groups to party vote shares. Analyses of the sources of these declines point to the importance of group size, suggesting that the changes we observe in election results and party strategies are likely to be long-lasting alterations in the electoral landscape of Western democracies.
