PR with a Vengeance: Bulgaria’s Electoral System in a Comparative Perspective

Bulgaria’s PR system with a 4% threshold was introduced in 1991 with the aim to ensure the ability of numerous and diverse parties to compete and enter Parliament, yet provide some extent of government stability. MPs are elected in 31 electoral regions from regional party lists, and proportionality is ensured at the national level with redistribution of seats if necessary. Despite repeated efforts to introduce a more majoritarian element in the system, a list PR system with preference vote remains in effect as of 2026. This paper assesses the impact of the electoral system on the number of parties in the system and the resulting party system fractionalization during the 36 year democratic history of the Bulgarian polity. Theoretically, it follows an endogenous institutions approach, viewing parties as vehicles for ambitious politicians to achieve their goals and the electoral system as a constraint on the likelihood of proto parties and established parties to form and remain active in the system (Spirova 2007, Aldrich 2001). Using district level data from Bulgarian national elections during the 1991-2024 period, the paper tests this proposition by looking at the proposed effect of the electoral threshold and other system requirements on the number of parties. It then also situates the outcome (the likelihood of new parties to emerge and old parties to persist) in comparative light by examining how other systems of similar nature impact party development. The paper expects to find a relatively higher number of parties in Bulgaria than in systems with comparable electoral constraints. Bulgarian party competition has proven to be quite unstable (Zankina 2017) with high fragmentation and newcomers winning elections in 2001, 2009 and 2021. It provides an explanation for this (expected) anomaly by looking at the electoral system in particular detail as well as engaging with alternative explanations of party emergence and persistence such as party financing regimes, and party voters linkages.