ABSTRACT
In representative democracies, political parties are simultaneously guarantors of stability and agents of change. On the one hand, they aggregate political demands (Almond and Powell 1966), structure electoral choice for the voters, and provide necessary (though not sufficient) conditions for stability in parliamentary decisionmaking (Aldrich 1995, Cox 1987, Müller 2000). At a more empirical level, the predominant patterns of party conflict in most advanced industrial and postindustrial societies have remained remarkably stable over the past century. The adaptability of political parties has contributed to this stabilization of political choice (Lipset and Rokkan 1967, Dalton 2006, Dalton and Wattenberg 2000a, Mair 1997). On the other hand, however, parties are organizations that do respond to economic, social, and political change in their environment. Some adapt to changing circumstances; others fail to do so and disappear; new parties emerge and sometimes rise to government status. In that sense, parties reflect change and are agents of political change at the same time (McDonald, Budge and Pennings 2004).
