The study of electoral systems and their consequences has a long history. It goes back as far as to Plinius the elder, and less far away to the Marquis de Condorcet, or to mathematicians like Borda, d’Hondt, and St. Laguë, or to politicians like Hamilton, Jefferson, and Hare. However, according to Riker (1982), only in the 1950s this field of research gained a scientific status thanks to the work of Duverger (1951). It is Duverger, in fact, the first scholar who conducted an extensive and rigorous empirical analysis on the effects of electoral systems on parties and party systems, leading to two (originally three) general propositions, which would later become known as his “law” and his “hypothesis”.
Such propositions have been the subject of academic debates that have continued for years and have regarded both their exact scientific status (Duverger, 1986; Riker, 1982; Sartori, 1968; 1986) and the direction of causality of the hypothesized relationships (Grumm, 1958; Nohlen, 1984; Rokkan, 1970). At any rate, they stimulated a flourishing of works about the variety of electoral systems applied in democracies (Bogdanor and Butler, 1983; Katz 1980; Lakeman, 1974; Nohlen, 1978), and about their consequences on the party systems in terms of what Duverger regarded as “mechanical effects” (mainly disproportionality and party fragmentation) (Rae, 1967; Taagepera and Shugart, 1989; Gallagher, 1992; Lijphart, 1994).
In the mid-eighties, however, Lijphart (1985) still complained about the backwardness of the discipline, especially with regard to the research on the effects of electoral systems on voters’ behavior (strategic voting) and on parties’ strategies (coalition building), i.e. the “psychological” effects highlighted by Duverger. It is exactly along this line of research that significant theoretical and empirical advances have been made in the following years, due also to a fruitful contamination of different approaches from the European and American traditions.
Cox (1997) is the first scholar that had the merit to integrate the game theoretical modelling of the American tradition and the empirical and comparative perspective of the European tradition into an original and unified framework for the analysis of electoral systems and their consequences. Based on the concept of strategic coordination, Cox’s work generalizes Duverger’s Law to multi-member elections, by positing that the number of viable candidates/lists in any individual district – under certain conditions that are explicitly pointed out — is limited by an upper bound of M+1 (M being the district magnitude). Moreover, and again under certain conditions (mainly related to the control of the executive), coordination – and therefore the M+1 rule — may take place at the system level, by projecting the local party systems into a national party system.
Meanwhile, the process of democratization under way in various countries, from Eastern Europe to Latin America, from Asia to Africa, has provided scholars of electoral systems the opportunity to broaden the scope of their analyses and to check whether theories developed mainly with reference to Western consolidated democracies would still be valid when applied to a larger and more diversified number of cases. Thus, comprehensive comparative analyses on the types and the effects of electoral systems have been conducted on new and old democratic countries (Colomer. 2004; Farrell, 2001; Gallagher and Mitchell, 2005; Golder, 2005; Norris, 2004) and even on all countries in the world (Reynolds, Reilly and Ellis 2005), while other works have focused either on certain geo-political areas such as post-communist Eastern Europe (Birch 2002; 2003), or on specific aspects of non-standard electoral systems such as, for example, the single transferable vote and the alternative vote (Bowler and Grofman, 2000), the single non-transferable vote (Grofman, Lee and Winckler Woodall, 1999), and especially the mixed electoral systems, which have had a widespread application in the last twenty-five years (Ferrara, Herron and Nishikawa, 2005; Moser and Scheiner, 2004; Shugart and Wattenberg, 2003).
Furthermore, in recent years some new themes have seen the light in the field of electoral system research. One is the process of electoral reforms (Ahmed, 2013; Boix, 1999; Colomer, 2005; Hazan and Leyenaar, 2012; Renwick, 2010), that have occurred in many countries after a long period of stability in the electoral rules. Another is the way electoral systems influence the selection of candidates and link together voters and representatives (Colomer, 2011; Ezrow, 2010). A third theme is related to how electoral systems contribute to shape the functioning of democracies (Lijphart, 1999; Powell, 2000), the quality of democracies (Diamond and Plattner, 2006) and, under particular circumstances, even the survival of democracies (Reilly, 2001).
The contribution of Italian political science to the comparative research on electoral systems has been quite relevant, starting with the seminal works of Sartori (1968; 1984; 1986; 1994) about the Duverger’s propositions and the refinement of the conditions of their validity. Other works are those of Fisichella (1984; 2008), Massari and Pasquino (1994), Pasquino (2006), Baldini and Pappalardo (2009), Chiaramonte (2005), and Chiaramonte and Tarli Barbieri (2011).
Since the 1990s Italy itself has become an interesting laboratory of new electoral systems, introduced in every tier of government, often by means of referendum, and later changed more than once (Giannetti and Grofman, 2011; Renwick, 2010). The first reform took place in 1991 and regarded the old proportional system, specifically the preference votes, that were diminished from up to four down to one (Pasquino, 1993). The second and the third reforms were far more radical: both of them took place in 1993 and called for the cancellation of proportional representation in electing, respectively, municipal and provincial councils, and the national parliament.
At the local level, the electoral reform of 1993 contained all the ingredients that would characterize the debate on future reforms: the direct election of the chief executive, two-rounds voting, the majority bonus (Agosta, 1999; Baldini and Legnante, 2000; Caciagli and Di Virgilio, 2005). At the national level, the mixed system introduced in 1993, instigated by the outcome of a referendum held in the same year, provided for 75% of the total seats being assigned in single-member districts by plurality and the remaining 25% allocated proportionally in multi-member districts (D’Alimonte and Chiaramonte, 1995). The main effects of the new electoral rules have been the establishment of a bipolar party system, characterized by high degree of fragmentation (Chiaramonte and D’Alimonte, 2004; D’Alimonte, 2003; 2004).
The fourth electoral reform of the 1990s occurred in 1995 and involved the regions. Together with the subsequent constitutional law no. 1/1999, it provided for the direct election of the president of the regional government by plurality and of the regional assembly through a mix system consisting of a majority bonus plus proportional representation. The new electoral system was meant to be majority-assuring, i.e. to guarantee the coalition of parties supporting the directly elected president the majority of the seats in the regional assembly (D’Alimonte 2000). The same 1999 constitutional reform, however, gave regions a large autonomy in choosing their own electoral systems. In the following years many regions took advantage of it and changed their electoral rules, but they did not reject the general model of a mix of proportional representation and majority bonus (Chiaramonte, 2007).
By 1999 all voting systems in the subnational tiers of government were based on proportional representation with a majority bonus. Only at the national level there was a different kind of mixed electoral system based on single-member districts and plurality rule with a PR quota. In 2005, however, a new (the fifth) electoral reform took place for the election of the national parliament. The majority bonus was introduced at this level too, though with significant differences in its functioning between the Chamber of deputies and the Senate (Chiaramonte and D’Alimonte, 2006; Chiaramonte and Di Virgilio, 2006). The merits and shortcomings of the new electoral system have been highly debated (Di Virgilio, 2007a; 2007b; D’Alimonte, 2007; Feltrin and Fabrizio, 2007; 2008; Pasquino, 2007). The system however did not survive the scrutiny of the Constitutional Court. At the end of 2014 the Court declared unconstitutional certain features of the system, namely the long closed lists and the mechanism for assigning the majority bonus. By cancelling the bonus and leaving intact the other rules for the distribution of seats, the Constitutional Court introduced de facto a proportional electoral system. However, in 2015 the Italian parliament passed once again a new electoral reform and reinstalled a mixed electoral system similar to that used until 2013. The major difference is that the majority bonus will be assigned to the list with most votes provided that its percentage is at least 40%. If no list will reach this threshold the top two lists will go to a second ballott. The winner of the runoff will get 54 % of the seats and the losers will be split the rest based on the votes they got on the first round. More than 20 years after its beginning, the process of electoral system change continues. Italy is still one of the most important laboratories of electoral engineering in the world.
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