Modeling party strategies and policy representation in multiparty elections: Why are strategies so extreme?

Existing spatial models of multiparty spatial competition have difficulty a ccounting for two related features of party behavior: that parties typicall y propose divergent policy programs, and that these programs are similar to , but more extreme than, the policies of their supporters. We expand and el aborate Iversen's "representational policy leadership" model, which combine s insights from the proximity and directional theories of voting, in an eff ort to explain this phenomenon. By developing a spatial model of party comp etition that incorporates voters' nonpolicy motivations (i.e., sociodemogra phic characteristics, retrospective economic evaluations, partisanship) and a mixed directional-proximity policy utility metric, we significantly impr ove our ability to explain parties' policy strategies, compared to alternat ive models that ignore either nonpolicy motivations or the directional comp onent of voters' policy utilities. We illustrate and test our arguments with conditional legit analysis of vot er choice for 1989 Norwegian election data. We show that a model that inclu des nonpolicy motivations in addition to proximity and directional motivati ons accurately accounts for the actual locations of parties but that the pr oximity and directional components alone are insufficient. Voters' nonpolic y motivations are crucial for explaining parties' policy strategies and als o for understanding the connection between parties' policy positions and th e positions of their supporters.