This is p. 181
new waves of voters. He concluded that it applied at least to Poland, which did adopt an extreme form of PR.
These exchanges of views on electoral impacts occurred outside any broad theoretical structure. Katz (1980) formulated a deductive theory "to explain the issue orientation, ideological style, and structural coherence (cohesion versus disintegration versus factionalism) of legislative parties" (p.13). The thrust of his theory was that "parliamentary party organization will appear as an extension of campaign organization, and hence will reveal the same structural characteristics as a rationally organized campaign" dictated by electoral rules (p.32). Based on eight assumptions of voters and electoral competition (pp.17-18), Katz proposed twelve hypotheses, for example:
5. Parties in large district PR systems will be more likely to be ideologically oriented than those competing in plurality systems.
Katz tested his hypotheses in two ways, with an extensive test involving cross-national data on parties and with an intensive test involving in-depth analysis of parties in Britain, Ireland, and Italy. Both tests supported most of his hypotheses. Other scholars had advanced similar findings, but Katz said, "There is a difference between knowing something to be so and understanding why" (p.117). His theoretical structure helped explain why parties differed according to electoral systems.
Our attention turns now to party theory, focusing on theories that involve individual parties as units of analysis. It is fashionable among party scholars at home and abroad to lament the lack of party theory. This complaint has a long and honorable history. Writing in French over fifty years ago, Duverger said:
We find ourselves in a vicious circle: a general theory of parties will eventually be constructed only upon the preliminary work of many profound studies; but these studies cannot be truly profound so long as there exists no general theory of parties (1963, xiii).
Duverger then spun out scores of bivariate generalizations, scattered widely over two hundred pages. Janda and King (1985) isolated nineteen major hypotheses in Duverger's book, tested them with cross-national data on approximately one hundred parties, and found statistical support for twelve. The keystone of Duverger's theorizing was the concept of party ideology. Because Duverger viewed leftist parties as the "modern" type, Janda and King used the concept of leftism in formalizing his hypotheses. Of the 12 supported hypotheses, eleven involved leftism as either a direct or indirect causal factor. The driving force of ideology in Duverger's theory is seen in Figure 1, the causal diagram that Janda and King devised for all twelve confirmed hypotheses, with specific variables identified by the major concepts in this review.
According to Figure 1, ideology (leftism) is the initial cause of virtually all organizational attributes in Duverger's bivariate propositions about party structure. In general, leftist parties tend to demonstrate more involvement by their members in party doctrine, more complexity in organizational structure, and more centralization of power. They do so because leftist parties are agents of social change (Hamilton 1989, 219), and parties need stronger organization to effect change than to defend the status quo. Even today, Duverger's theorizing dominates party research (Sartori 1976, x).
Despite Duverger's considerable success in his effort to "sketch a preliminary general theory of parties," scholars decades later still pleaded for party theory. In 1972, Mayer titled the chapter on parties in his comparative politics text, "The Search for a Theory of Parties." Acknowledging the stimulus of Duverger's book in 1976, Sartori observed that "there is still no general theory of parties" (1976, xi). Rewriting his comparative text nearly two decades later, Mayer still found that "research in any one aspect of parties tends to appear in isolation from other aspects of the topic without justification for the theoretical importance of the questions being asked" (1989, 142). In his recent review of the American parties literature, Crotty denied any "dominant perspective in the study of political parties" and saw party theory as "a goal to be sought" (1991, 148). In the English translation of his major book on political parties in Western democracies, von Beyme emphasized the importance of theory building to organize facts about parties, but sighed, "Complaints about a lack of satisfying theories are as old as party research itself and will certainly be directed against this study as well" (1985, 6).
In contrast to the view that we lack party theory, Schlesinger contends, "A theory has lain embedded in most of our writing on parties. We have, however, failed to see it as a whole" (1991, 4). I agree that we have complained too long about the lack of party theory. Over the years, a substantial body of theory has been built, and it is time to recognize the accomplishments. Perhaps party scholars have been expecting too much by