Electoral reform and fragmented polarization: New evidence from Taiwan legislative roll calls

This paper investigates how legislators respond to an electoral reform by adjusting their positions with respect to co‐partisans and rivals. Using cross‐sectional legislative roll calls over 20 years, we study how the dynamics of blue‐green confrontation are influenced by Taiwan's electoral reform from Single Non‐Transferable Votes (the SNTV) to Single‐Member Districts (SMD). Contrary to existing literature, our empirical evidence shows that the reform significantly fragmented legislator positions within their party and in relation to members from opposing parties, leading to an increase in contentious legislation and higher levels of both inter‐ and intra‐party distance. In the years following the reform, the political confrontation between the Kuomintang and the Democratic Progressive Party gradually diminished, eventually returning to levels seen before the reform. Moreover, our analysis reveals that the 2008 reform had heterogeneous effects on different parties, with each party displaying varying levels of resilience in response. This finding contributes to electoral system literature, providing policy implications for democratic countries contemplating electoral reforms.