ABSTRACT Objectives Political polarization has intensified across democracies, shaping increasingly extreme political landscapes and posing significant challenges to effective governance. Despite extensive research on polarization, the fundamental determinants of party polarization remain contested. This study investigates public opinion, specifically political trust, as a critical yet underexplored factor influencing party polarization, offering a fresh perspective on its impact in diverse democratic contexts. Methods This study employs a linear regression model using the integrated datasets from 1971 to 2016, from the AmericasBarometer, American National Election Studies (ANES), Eurobarometer, World Value Survey (WVS) Wave 5, and the Varieties of Democracy (V‐Dem) project's V‐Party database. Results Contrary to conventional arguments, ideological polarization does not display a significant association with party polarization in the general model and shows mixed effects across specific policy domains. At the same time, it has a positive influence on party divergence in presidential systems. In contrast, trust polarization emerges as a significant and consistent force driving party polarization. Conclusion These findings challenge traditional frameworks prioritizing ideological alignment as the primary driver of party polarization, reframing the discussion to emphasize trust polarization as a central determinant. By offering new insights into the interplay between public trust in government and party behavior, this study contributes to a deeper understanding of party polarization and provides implications for democratic stability.
Solbi Kim (Thu,) studied this question.