Do candidates serve parties interests? Party polarization as a discipline device

In this paper we model the interaction between parties and candidates to highlight the mechanisms by which parties selecting candidates may discipline legislators. Parties are long-lived organizations providing incentives to short-lived candidates. The incentive problem parties face is very similar to the problem faced by firms that try to motivate workers. However parties are different from firms as the coincidence of interests between candidates and parties goes beyond the end of the political carrier of candidates. This happens because current candidates care about their future utility as citizens and parties may affect future public policies. We suppose that citizens have preferences over a multimentional policy space comprising an ideological and a monetary dimension. Candidates are policy motivated on the ideological dimension only. Hence they care more about winning elections the bigger the ideological distance from the candidate of the opponent party. Therefore, parties can use strategically polarization to provide incentives to candidates. Because of this strategic use, the polarization of the political race does not always reflect the polarization of voters’ preferences. In particular, when the polarization of preferences is low, parties may choose to increase the polarization of the political race to discipline candidates. On the other hand, if the polarization of preferences is high, parties may choose less extreme candidates to get closer to the median voter. In general, the polarization of the political race seems to be a compromise between policy preferences of party members and electoral goals.