Two fundamental choices that confront architects of new democratic constitutions are those between plurality elections and proportional representation (PR) and between parliamentary and presidential forms of government. The merits of presidentialism and parliamentarism were extensively debated by Juan J. Linz, Seymour Martin Lipset, and Donald L. Horowitz in the Fall 1990 issue of the Journal of Democracy.1 I strongly concur with Horowitz's contention that the electoral system is an equally vital element in democratic constitutional design, and therefore that it is of crucial importance to evaluate these two sets of choices in relation with each other. Such an analysis, as I will try to show, indicates that the combination of parliamentarism with proportional representation should be an especially attractive one to newly democratic and democratizing countries.
The comparative study of democracies has shown that the type of electoral system is significantly related to the development of a country's party system, its type of executive (one-party vs. coalition cabinets), and the relationship between its executive and legislature. Countries that use the plurality method of election (almost always applied, at the national level, in single-member districts) are likely to have two-party systems, one-party governments, and executives that are dominant in relation to [End Page 72] their legislatures. These are the main characteristics of the Westminster or majoritarian model of democracy, in which power is concentrated in the hands of the majority party. Conversely, PR is likely to be associated with multiparty systems, coalition governments (including, in many cases, broad and inclusive coalitions), and more equal executive-legislative power relations. These latter characteristics typify the consensus model of democracy, which, instead of relying on pure and concentrated majority rule, tries to limit, divide, separate, and share power in a variety of ways.2
Three further points should be made about these two sets of related traits. First, the relationships are mutual. For instance, plurality elections favor the maintenance of a two-party system; but an existing two-party system also favors the maintenance of plurality, which gives the two principal parties great advantages that they are unlikely to abandon. Second, if democratic political engineers desire to promote either the majoritarian cluster of characteristics (plurality, a two-party system, and a dominant, one-party cabinet) or the consensus cluster (PR, multipartism, coalition government, and a stronger legislature), the most practical way to do so is by choosing the appropriate electoral system. Giovanni Sartori has aptly called electoral systems "the most specific manipulative instrument of politics."3 Third, important variations exist among PR systems. Without going into all the technical details, a useful distinction can be made between extreme PR, which poses few barriers to small parties, and moderate PR. The latter limits the influence of minor parties through such means as applying PR in small districts instead of large districts or nationwide balloting, and requiring parties to receive a minimum percentage of the vote in order to gain representation, such as the 5-percent threshold in Germany. The Dutch, Israeli, and Italian systems exemplify extreme PR and the German and Swedish systems, moderate PR.
The second basic constitutional choice, between parliamentary and presidential forms of government, also affects the majoritarian or consensus character of the political system. Presidentialism yields majoritarian effects on the party system and on the type of executive, but a consensus effect on executive-legislative relations. By formally separating the executive and legislative powers, presidential systems generally promote a rough executive-legislative balance of power. On the other hand, presidentialism tends to foster a two-party system, as the presidency is the biggest political prize to be won, and only the largest parties have a chance to win it. This advantage for the big parties often carries over into legislative elections as well (especially if presidential and legislative elections are held simultaneously), even if the legislative elections are conducted under PR rules. Presidentialism usually produces cabinets composed solely of members of the governing party. In fact, presidential systems concentrate executive power to an even greater [End Page 73] degree than does a one-party parliamentary cabinet—not just in a single party but in a single person.
Explaining Past Choices