Towards the Centre?: The Dynamics of Two-Party Competition
Polarized two-party systems provide the simplest form of political competition in electoral democracies. Each of the two parties offers the electorate a clear set of policy orientations and issue positions and the party closest to the preferences of the voting majority wins. Such straightforward models lie at the heart of some of the most persuasive accounts of electoral competition we have.
Electoral competition provides the dynamic force that stimulates change in parties' ideological orientations, policy positions, and organizations. In his influential book, An Economic Theory of Democracy, Anthony Downs ( 1957) argued that simple two-party competition would inevitably lead the parties to locate themselves immediately adjacent to one another at the centre. Not to do so would be irrational for a power-seeking party as it would guarantee victory to a more centrist opponent and condemn it to permanent electoral minority status.
Downs' argument focuses on the issue positions parties ought to take as a consequence of their competitive situation. Kirchheimer ( 1966) pushed this analysis of party systems considerably further by demonstrating the organizational consequences of this logic. He pointed out that modern cadre parties, which he labeled catch-all parties, were inherently better organized than mass parties to make the necessary (Downsian) policy adjustments. As a consequence (left-wing) mass parties had either to adopt many of the forms and mores of their (conservative) catch-all opponents or suffer long-term decline and continuing electoral defeat. His conclusion, based on a detailed study of the German Social Democrats, was that these