development do not fair well in one of the most favorable cases, then presumably additional research will do little to reduce the competing number of theories and our attention has instead be refocused on re-specifying them. Second, postwar Germany is an empirical gold mine; it provides data for virtually every conceivable variable, and does so across time, sub-national levels and individual parties. It offers within-case variation that is sufficient to provide preliminary tests of heretofore untested theoretical claims. (Gerring 2007, 50-53, 57-59) Third, the study of a single case like Germany makes it easier to address problems common during early stages of theory development. Very often little is known about causal mechanisms because initial theoretical claims are poorly specified and overly general. (Alexander and Bennett 2004, 204-08; Gerring 2007, 43-45). Interaction effects among variables are insufficiently understood and difficult to control for with large N, cross-sectional research designs. (Alexander and Bennett 2004, 21-22; Hall 2003, 380-82; Ragin 1994, 136-39) And, temporal structures are overlooked which can play an important role in historical phenomena like the formation of party systems. Transitional party systems could have temporal structures like tornadoes with a quick cause and quick effect or they could function like global warming where long-term, slow moving causes have long-term and slow effects. (Pierson 2003, 178-79) Such temporal structures have important theoretical implications and thus require the sort of close attention only possible through a case study approach.
The paper is organized into four sections. First, I review the literature on party system formation and group the various explanations according to whether they emphasize institutional, historical or strategic factors. Second, I discuss the strengths and shortcomings of institutional factors – the most frequently cited and theoretically most advanced in the literature – in explaining postwar Germany’s rapid party system institutionalization. Third, I analyze the importance historical and strategic factors played in the formation of Germany’s party system and how the interact with each other. Fourth, I draw the implications the German case for the broader understanding of party system formation.
I. THREE APPROACHES TO EXPLAINING PARTY SYSTEM FORMATION