When parties are not teams: party positions in single-member district and proportional representation systems

Abstract

1 We wish to thank Kristen Kanthak, Jiyoon Kim, Rebecca Morton, and participants at workshops at Harvard University and Princeton University for their comments. Please direct all communications to James M. Snyder, Jr., at jsnyder@gov.harvard.edu. Keywords: political economy; elections; political parties. JEL classification, 1235: Political Economy. AbstractTheoretical analyses of party positions commonly assume that parties act as teams to maximize their legislative representation. This assumption runs counter to another line of theorizing in which individual legislators maximize their own chances of winning reelection.To resolve this tension, the paper presents a model of party platform choice that relaxes only the assumption that parties are teams in the classical two-party spatial model. Platforms are chosen by majority rule among all legislators within a party. Politicians seek to win their own seats in the legislature, but they must run under a common party label. In both singlemember district and proportional representation systems, equilibrium platforms are shown to diverge substantially, with one party located near the 25th percentile of the voter distribution and the other near the 75th percentile, rather than converge to the median. The model also yields predictions concerning short-term economic shocks, incumbency advantages, and gerrymandering.1

Unintentional Gerrymandering: Political Geography and Electoral Bias in Legislatures

“…Beyond the electoral bias in the transformation of votes to seats that we illustrate in this paper, Ansolabehere et al (2012) describe another, more subtle impact of the asymmetric distribution of partisans across districts. It is conceivable that because of the extent to which liberals are packed into urban districts, the Democratic platform, or at least its perception by Florida voters, is driven by its legislative incumbents -a small group of leftists from Miami-Dade and Broward counties who never face Republican challengers -which in turn makes it difficult for the party to compete in the crucial moderate districts.…”

Do direct-democratic procedures lead to higher acceptance than political representation?

“…It would be interesting to explore the role of institutions like plurality versus proportional election systems or pluralist versus corporatist interest intermediation. While the degree of party divergence is similar under proportional representation and plurality rule (Ansolabehere et al 2012), both may constrain the perceptions of procedural legitimacy in complex ways. Furthermore, the institutions may themselves be a result of underlying cultural traits and preferences for majoritarianism or consensualism (for a related finding on judicial reviews of controversial issues, see Fontana and Braman 2012).…”

Cracking the whip: spatial voting with party discipline and voter polarization

“…This contrasts to, for example, the model in Snyder (1994), where although parties (slightly) differentiate their platforms, every incumbent legislator is reelected with certainty. The uncertainty regarding the winner of contested seats likewise is endogenous to my model, as opposed to resulting from exogenous shocks such as in Ansolabehere et al (2012). The result of some whipping, but not complete party power, also reflects an empirical reality seen across countries, suggesting that while parties are influential, legislators also are able to vote as they please in at least some votes.…”

“…The second paper in this vein, Ansolabehere et al (2012), takes the same basic principle of letting incumbent legislators decide the next election's policy, but adds in random shocks, representing something like a 'scandal,' which parties cannot influence, but affects voter choices. Because of the risk of a scandal causing a legislator to lose her seat, incumbents have stronger preferences over party policy; in the Snyder (1994) paper, so long as the constituency's median voter slightly prefers party x's policy, the x candidate would win with certainty.…”