Party competition over time : How voters and intra-party structure constrain party policy shifts

This work is an analysis of party policy change over time. So far, the predominant models of party competition are static. They study each election in isolation thereby assuming, in effect, that parties choose policy platforms from scratch. I argue that integrating the time dimension in theories of party competition allows for a more realistic perspective on party behavior. The dissertation identifies factors that account for the differences in the constraints parties face when shifting their policy positions, namely voters’ perception of party policy changes and the parties’ internal structures. I adapt Zaller’s (1992) Receive-Accept-Sample (RAS) model to party position shifts arguing that the perception of party policy shifts is a two-stage process in which voters first receive information on the parties’ claims and then decide whether the claims are credible (i.e. whether they accept them). Voters only perceive a party’s position shift if they both receive and accept the party’s shift message. Whereas the first step is a cognitive process, the latter is a function of the party’s credibility. Using micro-level data of several panel election studies in the United Kingdom, the analysis of voter perceptions of party policy shifts reveals that there are differences across voters (and parties) which can by explained by covariates that affect the likelihood of receiving and accepting information on party position shifts. Using the two-stage model how voters perceive party position shifts, I draw conclusions which parties face higher constraints when shifting their policy platforms. Studying party policy shifts in ten West European countries from 1945 until 2005, the empirical results support most of the postulated effects. The findings show that voters constrain party policy shifts. Because systematic differences exist in the voters’ evaluation of party policy shifts, some parties are more constrained in shifting their party platforms than others. Beyond voters and their perceptions of party position shifts, parties are also constrained by their respective intra-party structures. I therefore study the consequences of the members’ role within political parties and how the intra-party distribution of power affects party position shifts. I find that the relevance of party members as workforce and intra-party decision-making rules determine whether parties are able to move away from the status quo. Although I find no empirical evidence that sources of party income affect the parties’ policy behavior, I conclude that a party’s internal structure affects its ability to shift policy positions. The findings presented in this dissertation have important implications for our understanding of party policy behavior, models of party competition, party organizations, and voting behavior