Change of Electoral Magnitude: Impacts on Parties, Voters and Party system

• In Event: Electoral Rule Reforms and Mistakes

Abstract

Most of time, electoral reforms simultaneously affect several components of electoral systems (formula, magnitude, thresholds, size of the assembly, constituencies, ...) and, consequently, it is difficult to isolate their respective effects. The French European elections provide a rare opportunity to evaluate the impact of the change of a single component, the magnitude, one of the most, or even the most important, component of electoral systems (Duverger, 1951; Rae, 1967; Taagepera, Shugart, 1989; Taagepera, Shugart, 1992; Benoit, 2001; Zinger, Gershman, 2018 ...), because it has been amended twice since the first elections in 1979, while all other components of the electoral system have remained unchanged over time (PR with an electoral threshold of five per cent for the distribution of seats).

In 2019, French European elections will be held within a single national constituency, as in the period 1979-1999, an electoral system which was temporarily abandoned in 2004 with the division of the national territory into 8 constituencies of different sizes. In 2004, that reform had confirmed that magnitude plays a unique role : the smaller magnitude benefited to strong parties; the proportionnality of the electoral system decreased; parties and voters adapted their electoral strategy according to the size of their constituency (Dolez, Laurent, 2010). The return to the system originally set up in 1979 gives us the possibility of re-examining this issue. More precisely, our goal is two-fold: to put into a long-term perspective (9 ballots) effects of the two successive changes of magnitude on both the levels of disproportionality and fragmentation of the party system; to assess immediate "mechanical and psychological effects" of the change of magnitude, by comparing the results before and after each amendment: i.e., in 1999/2004, then in 2014/2019.

References (in the order of their quote)

DUVERGER M., Les partis politiques, Paris, Éditions Armand Colin, 1951.
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TAAGEPERA R., SHUGART M., «Predicting the Number of Parties : A Quantitative Model of Duverger’s Mechanical Effect », American Political Science Review, vol. 87, n°2, 1993, vol.87,(2), 455-464
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DOLEZ B., LAURENT A. " La magnitude, le facteur décisif ? Les élections européennes de 2004 en France et les effets du changement de mode de scrutin", Revue internationale de politique comparée, 2010/3, Vol. 17, 175- 193

Authors

• Annie Laurent, Universite de Lille

• Bernard Dolez, Université Paris 1