Political parties are an inextricable feature of democratic government, yet their arrangement, function and number often reflect significant variation. Interestingly, these and other similar characteristics are often used to describe and classify the party systems of different polities. While these tasks may appear relatively simple, significant debate in the literature as to the "proper" method suggests otherwise. With the goal of developing a greater understanding of party function in a polity, the following paper examines some of the major bones of contention in the study and classification of political party systems such as appropriate definition for party and party systems, factors determining a parties' inclusion in a classification count, criteria for a parties' relevance or credibility, and the roles of behavior, competition, and party unity. As with all inquiries, the first major task involves definitions.
Potter Stewart, former Associate Justice of the U.S. Supreme Count, once commented on pornography, "[I cannot define it.] But I know it when I see it." Much the same can be said of political parties in the sense that they are recognizable but difficult to define. Fortunately, given that this discussion focuses on party systems, we are not required to outline a precise definition for political party. Instead, we are only concerned with definitions of party as they relate to the classification of systems. For this, we must turn to the literature.
Giovanni Sartiori's "A Typology of Party Systems," (1976) provides two specific rules for determining the relevance of a particular party. The first rule argues "a minor party can be discounted as irrelevant whenever it remains over time superfluous, in the sense that it is never needed or put to use for any feasible coalition majority." In this sense a party should not be counted for classification purposes if it fails to exhibit coalitional potential. The second rule argues that "a party qualifies for relevance whenever its existence, or appearance, affects the tactics of party competition and particularly when it alters the direction of the competition." Here a party is not counted for classification unless it demonstrates blackmail potential. In Sartori's view, a party only needs to exhibit one of these qualities to be considered relevant.
Sartori's "relevance criteria" are unique because they remove the question of electoral returns and competition. Many authors such as Blondel (1968) and Rokkan (1970) base their analysis on the number of seats obtained in the series of Lower House elections or on electoral thresholds, but this method ignore alternative forms of party influence on government. In short, neither the Sartori nor the electoral method is solely adequate for determining a parties' relevance for classification; ideally, a combined approach should be employed. Unfortunately, determining the relevance of a party only addresses one feature of party systems, the number of parties, without considering their relative size. In Political Parties and Party Systems (1996), Alan Ware provides an approach that classifies systems based on the relative size of parties.
Using the percentage of legislative seats as criteria, Ware outlines four main types of party systems: (1) two-and-a-half party systems, (2) systems with one large party and several much smaller ones, (3) systems with two larger parties and several much smaller ones, and (4) even multiparty systems. This approach "assumes that the behavior of a party system is likely to be influenced by the size of a party's opponents in relation to its own size." In essence, the structure of competition and cooperation should vary across the different type of systems, thus highlighting a need for consideration of relative size.
The issue of behavior and competition is also discussed by Sartori, though in a slightly altered sense. "The key to understanding it is that for Sartori the crucial feature of any party system is not how competitive a party system is but the direction of party competition" (Ware 1996). This idea is heavily concerned with the ideological positions of parties in a polity and success as determined by the type of competition. In particular, the distinction is made between centripetal drives and centrifugal drives. In the former, competition is pulled toward the centre of the political spectrum. In the latter "the political centre becomes weakened as voting moves to one or both of the extremes, and parties thereby have incentives to take on extreme policy position (Ware 1996). Sartori's combines this idea with party fragmentation (presence of many parties with none approaching the absolute majority point) to present his four categories of party systems two-party, moderate multiparty, segmented multiparty, and polarized multiparty (Sartori 1976)
A final way of conceptualizing party systems can be found in Robert Dahl's "Party System and Patterns of Opposition" (1966). In an effort to combine the issues of "number of important parties" and "internal unity of party," Dahl offers four categories: (1) two party systems with a high degree of internal party unity, (2) two-party systems with relatively low internal party unity, (3) multiparty systems with relatively high internal party unity, and (4) multiparty systems with low internal party unity. Once again the structure of competition seems to be the main focus. The argument is that the number competitiveness of opposition within a system is a function of both the number and nature of parties, i.e. "the extent to which opposition is concentrated (1966).
Classifying a party system appears, prima facie, no more difficult than counting the number of parties in a polity and classifying the system accordingly: two parties, a two-party system; three parties, a three-party system: more than three parties, a multi-party-system. However, this paper has demonstrated difficulties associated with such a task. A researcher must deal with question related to the appropriate definition for party and party systems, factors determining a parties' inclusion in the count, criteria for a parties' relevance or credibility, and the roles of behavior, competition and party unity. As shown, these issues often lead to very distinct typologies of party systems. Hopefully continued research and discussion of the issues listed above will lead to the development of adequate typology that incorporates the view of all sides.
Blondel, Jean. 1968. "Types of Party System" in The West European Party System. 1990. Oxford: Oxford University Press. pp. 302-310.
Dahl, Robert A. 1966. "Party Systems and Patterns of Opposition" in The West European Party System. 1990. Oxford: Oxford University Press. pp. 296-301
Rokkan, Stein. 1970. "The Electoral Balance" in The West European Party System. 1990. Oxford: Oxford University Press. pp. 311-315
Sartori, Giovanni. 1976. "A Typology of Party Systems" in The West European Party System. 1990. Oxford: Oxford University Press. pp. 316-349
Ware, Alan. 1996. Political Parties and Party Sytems. Oxford: Oxford Univesity Press.