A Behavioral Theory of Competitive Political Parties

The rational choice tradition has generated three models of competitive political party behavior: the vote-seeking party, the office-seeking party, and the policy-seeking party. Despite their usefulness in the analysis of interparty electoral competition and coalitional behavior, these models suffer from various theoretical and empirical limitations, and the conditions under which each model applies are not well specified. This article discusses the relationships between vote-seeking, officeseeking, and policy-seeking party behavior and develops a unified theory of the organizational and institutional factors that constrain party behavior in parliamentary democracies. Vote-seeking, officeseeking, and policy-seeking parties emerge as special cases of competitive party behavior under specific organizational and institutional conditions. Since Downs (1957), rational choice theories have come to play an increasingly important role in the study of competitive political parties. Efforts to develop such models of political parties have been of tremendous benefit to political science. Theories based on simple assumptions of party and voter objectives have generated influential (though often controversial) results. But even though rational choice models of political parties have been both powerful and suggestive, they have failed to generate any single, coherent theory of competitive party behavior or to produce robust results that apply under a variety of environmental conditions. There is little theory to help us choose between existing models, and where their assumptions fail, we are often left in the dark. Arguably the defining characteristic and virtue of rational choice theory is precisely its resistance to ad hoc explanation and its quest for equilibrium results independent of structural peculiarities. However, neoinstitutionalists, both within and outside the rational choice tradition, have recently challenged this conception of "pure theory" (March and Olsen 1984; Schlesinger 1984; Shepsle 1979). Moreover, the reluctance of many rational choice theorists to apply their models of electoral competition beyond individual candidates in simple institutional contexts has limited their influence on the empirical study of parties. My objective in this article is to provide a framework in which to explain