Taiwan’s partisan politics have long centered on Cross-Strait relations with Mainland China, yet over the past decade, cultural and moral issues—such as same-sex marriage, the death penalty, and surrogacy—have introduced new axes of division and intensified polarization. This article traces how civic groups and party actors during the same-sex marriage campaign and the Sunflower Movement framed and mobilized moral debates, and it uses two decades of Taiwan Social Change Survey data to show the rise of issue partisanship around civil rights and family values in the mid-2010s. These cultural cleavages persisted through 2020 without displacing Cross-Strait relations as the dominant divide. Taiwan’s case illustrates how cultural polarization can develop within a geopolitically constrained democracy and East Asian context, contributing to comparative debates on culture wars and partisan polarization.
