Mixed-Member Electoral Systems in Constitutional Context

Over the past few decades, political reformers have embraced mixed-member electoral systems as the “best of both worlds.” Whereas single-member district (SMD) systems offer accountability between representatives and voters, proportional representation (PR) systems in which the composition of the legislature reflects the relative proportion of the votes received by the various political parties offer equity. In a mixed-member electoral system, accountability and equity come together because a certain number of legislators are elected in SMDs under plurality rule and the remainder are elected in multi-member districts under some version of PR. Currently, 32 countries as dissimilar as Mexico, Ukraine, South Korea, Jordan, Hungary, Mongolia, and Germany use some variation of a mixed-member electoral system. In this volume, a group of internationally-recognized political scientists evaluate the ways in which the introduction of a mixed-member electoral system affects the configuration of political parties. The contributors examine several political phenomena, including cabinet post allocation, nominations, pre-electoral coalitions, split-ticket voting, and the size of party systems and faction systems. Significantly, they also consider various ways in which the constitutional system—especially whether the head of government is elected directly or indirectly—can modify the incentives created by the electoral system. Part I of the book provides an in-depth comparison of Taiwan and Japan, both of which moved from single non-transferable vote systems to mixed-member majoritarian systems.