Why vote-seeking parties may make voters miserable

This paper explores an unexpectedly hard question for representative democracy, which is usually thought to be enhanced when political parties compete with each other for the support of voters in free and fair elections. Defining optimal representation in terms of the probability that a voter will find a party to support at election time that promotes a policy position close to his/her ideal point, it transpires that vote-seeking parties do not deliver optimal representation. They tend to locate 'too close' to the centroid of voter ideal points to minimize the aggregate distance between party positions and voter ideal points. Instead, optimal representation in this sense will be delivered if parties set policy positions using 'aggregator' rules, which seek to represent the views of current party supporters, but not to attract new supporters. One policy implication is that the representativeness of inter-party politics is increased by enhancing the representativeness of intra-party politics.