Positioning under Alternative Electoral Systems: Evidence from Japanese Candidate Election Manifestos

We study a core question of interest in political science: Do candidates position themselves differently under different electoral systems and is their positioning in line with the expectations of spatial theories? We use validated estimates of candidate ideological positions derived from quantitative scaling of 7,497 Japanese-language election manifestos written by the near universe of candidates who competed in the eight House of Representatives elections held on either side of Japan's 1994 electoral reform. Leveraging variation before and after Japan's electoral reform, as well as within each electoral system, we find that candidates converge in single-member districts and diverge in multimember districts, and converge on copartisans when not faced with intraparty competition and diverge when they do. Our study helps to clarify debates about the effects of electoral systems on ideological polarization and party cohesion in Japan and more generally.