Does the way we vote affect political polarization? This paper examines how electoral rule disproportionality influences platform polarization. We built a Downsian model with parties that are mainly policy-motivated and found that greater electoral inequality leads to less ideological divergence between platforms. However, measuring polarization by party distance versus using the Dalton index changes this relationship significantly. Our analysis shows the number of parties increases polarization when measured as the gap between extreme positions but not when using a more balanced metric. Using data from over 300 elections worldwide, we confirm these theoretical findings suggest electoral systems themselves play a major role in shaping political discourse divergence.

📊 Data & Methods

* Downsian electoral competition model

* Incorporates policy-motivated and/or ideological parties

* Analyzes polarization using two distinct measures: (a) distance between extreme platforms, (b) Dalton index

* Empirical analysis based on a dataset of >300 elections across various countries

🔍 Key Findings

* Polarization measured by platform distance decreases as electoral disproportionality increases

* The number of parties positively affects polarization when measuring the gap between extreme platforms

This relationship does not* hold for the Dalton index

🧠 Policy Implications

* Electoral system design significantly shapes political discourse and representation outcomes