In This Article Electoral Volatility in the New Democracies of Latin America

  • Introduction

Political Science Electoral Volatility in the New Democracies of Latin America
Mariano Torcal
  • LAST MODIFIED: 29 November 2018
  • DOI: 10.1093/obo/9780199756223-0256


The topic of electoral volatility was not at the center of academic work in Latin America until the seminal Building Democratic Institutions: Party Systems in Latin America (Mainwaring and Scully 1995) (cited in Electoral Volatility as an Expression of Party System Equilibrium). Preceding analyses primarily focused on explaining the breakdown of democratic politics in the region during the 1960s and 1970s. Conventional wisdom that departed from the classic work of Sartori in Parties and Party Systems (Cambridge: Cambridge University Press, 1976), maintained that stable party systems are crucial for the durability of democracies, focusing his attention on aspects such as party system polarization and fragmentation. Mainwaring and Scully 1995 shifts the discussion, arguing that previous literature on the region neglected and inadequately conceptualized an equally important property of party systems: their level of their institutionalization. According to Mainwaring and Scully, party system institutionalization (PSI) is formed by four different dimensions. The first is stability in the patterns of party competition. Thus, institutionalized party systems are those in which actors develop expectations, orientations, and behavior based on the premise that practices and organizations will prevail into the foreseeable future. Mainwaring 2018 (cited in Electoral Volatility as an Expression of Party System Equilibrium) argues that this is the only relevant dimension in PSI, while considering that the other three are just underpinnings that facilitate it. So according to this work, an institutionalized party system is the one in which a stable set of parties interacts regularly in stable ways. This stability of interparty competition is traditionally measured with the Pedersen volatility index, a comprehensive measure of the net systematic shift in levels of electoral support for parties across elections. As volatility is negatively correlated with this important dimension of party system institutionalization, conventional wisdom holds that political representation deteriorates when there is persistent high volatility. To this debate, the well-cited Mainwaring and Torcal 2006 (cited in Electoral Volatility as an Expression of Party System Equilibrium) adds the idea that this lack of stability in the patterns of competition in party systems, measured by electoral volatility, is a typical characteristic of new and developing democracies. According to that study, the most important defining characteristic of party systems in less developed countries is captured by their lack of institutionalization, in other words, the amount of electoral volatility in their party systems. Since publication of these three contributions, the debate about party systems dynamics in the region has been focused on studying the patterns of party system competition using different measures of electoral volatility.

General Overviews

Not surprisingly, during the last two decades studies on democratization and resurgent multipartyism have been accompanied by an increasing attention to party system institutionalization and more concretely, by the study of the stability in the patterns of party competition, measured by different variations of electoral volatility. These studies have opened a comparative debate about the effects of the instability of the patterns of party competition that goes well beyond the new democracies in the Latin American region. The following article, although mostly focused on Latin America, is dedicated to discuss the comparative literature on this topic. It first addresses the debate about how different measures of electoral volatility might constitute an expression of party system equilibrium. The idea is not so much about the electoral instability itself, but instead the instability of the equilibrium that should exist in the patterns of party competition. Political accountability requires healthy patterns of competition and therefore electoral volatility; the problem is how to capture the lack of party system institutionalization (PSI) while setting aside the volatility produced by political accountability. The following presents the different contributions about how to capture this lack of equilibrium using different indicators of electoral volatility. This literature review is again comparative, with Latin America as one of the regions under study. A comparative debate on the effects of the lack of party system equilibrium in the functioning of representative democracies closes this article.

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