選挙制度が押し広げる歪み

抄録

The Japanese election system has many distortions. Malapportionment, both in the Lower House and Upper House, gives the Liberal Democratic Party (LDP), which is based in the rural areas, a huge advantage, while putting the other parties, based in urban areas, at a disadvantage. It was difficult for the Democratic Party of Japan (DPJ) to get seats in rural areas and they even lost their seats in the urban areas. The Second House (Upper House) is very influential in Japanese politics. The Single Non-Transferable Vote (SNTV) system that is followed in the Upper House gives no decision-making powers to the two-member districts and multiparty breakups to the three- and five-member districts. Significant decision-making power is concentrated in single-member districts, which are in rural areas, and this distorts the decision making even more. SNTV in local assemblies causes a contamination effect in the single-member districts in the National Diet, especially in urban areas. Japan should reform its apportionment system to ensure Pareto improvement or economic efficiency. It should also do away with SNTV elections and establish a two-party system. Apportionment of electoral districts by age bracket, with Demeny voting as an option, could be yet another interesting idea for the national government to consider.