(iPoster) The Impact of Electoral Reform on District-Level Party Systems

• In Event: Poster Session: Crime, Violence, Institutions in Comparative Politics

Abstract

Understanding the causal impact of electoral reforms is particularly crucial in new democracies, where institutional changes can have profound and lasting effects on the political landscape. In these contexts, where democratic institutions are often still evolving, changes to electoral rules can significantly influence party systems, voter behavior, and the overall stability of the democratic process. Theories of institutional design suggest that the way electoral systems are structured, including elements like district magnitude and the type of electoral system, can shape the nature of political competition and representation. However, empirical evidence on how these changes play out in practice, particularly in new democracies, is still limited. This makes it essential to explore the causal relationships between electoral reforms and party system dynamics in these contexts.

To fully understand the relationship between party systems and institutions, it is necessary to examine these dynamics at the district level. While national-level analyses provide valuable insights, district-level studies allow for a more nuanced understanding of how electoral reforms affect political competition on the ground. Districts often vary significantly in terms of size, demographic composition, and political context, making them ideal units for analyzing the effects of institutional changes. By focusing on the district level, research can better capture the localized impact of reforms, such as changes in district magnitude, and how these reforms influence the effective number of parties (ENP). Understanding these dynamics at the district level is particularly important in new democracies, where institutional reforms are often implemented unevenly across different regions, leading to varying outcomes in party system development and democratic consolidation.

This study proposes to examine the interaction between institutions and party systems at the district level in Chile, a burgeoning new democracy. It particularly focuses on local municipal elections, which are conducted using a parallel electoral system, in which voters engage in both first-past-the-post (FPTP) elections for mayors and proportional representation (PR) elections for local councillors. Given that the size of districts is adjusted automatically as populations increase or shrink, it presents an ideal opportunity to study how institutional adjustments impact party competition at the local level. Additionally, the parallel electoral system provides a unique context in which the combination of centripetal and centrifugal forces within the party system can be explored simultaneously.

While the subnational approach allows us to better leverage the causal mechanisms between institutions and party system fragmentation, looking at parallel electoral systems helps isolate potential coattail effects and other confounding factors that could distort the underlying nature of party competition patterns.

The remainder of this article is structured as follows. In the next section we review the existing literature on electoral systems and party fragmentation, with a particular emphasis on the dynamics in new democracies. In Section 3 we present the Chilean case in detail, focusing on the electoral system used for local elections and the institutional reforms that affect district magnitude. In Section 4 we outline the data sources and analytical techniques employed, including the difference-in-differences approach and mixed-effects models. In the results section we present the key findings, highlighting the impact of changes in district magnitude on the effective number of political parties. Finally, we conclude with a discussion of the broader implications of these findings for the study of electoral reform and party systems in new democracies and offer a summary of lessons useful in the context of new democracies with high rates of institutional reform turnover.

Author

• Kenneth Bunker, Universidad San Sebastian