Although spatial theory posits that political parties adjust their policies in response to rival parties’ policy strategies, there is little comparative research that evaluates this hypothesis. Using the Comparative Manifesto Project data, we analyse the relationship between parties’ policy programmes and the policies of their opponents in twenty-five post-war democracies. The authors conclude that parties tended to shift their policy positions in the same direction that their opponents had shifted their policies at the previous election; furthermore, parties were particularly responsive to policy shifts by other members of their ‘ideological families’, i.e. leftist parties responded to other leftist parties while right-wing parties responded to right-wing parties. Their findings have important implications for spatial models of elections, for the dynamics of party systems and for political representation.
(Online publication April 07 2009)
* Department of Political Science, University of California at Davis (email: firstname.lastname@example.org and email@example.com, respectively). Both authors contributed equally to this article. An earlier version was presented at the Annual Meeting of the American Political Science Association, Philadelphia, 2006. The authors thank Brad Jones, Cindy Kam, Jonathan Katz, Heather Stoll and Guy Whitten for helpful advice relating to the statistical analyses reported in this article, and three anonymous referees for very detailed and thoughtful comments. All remaining errors are the authors’ sole responsibility.