Several Upper House electoral districts are set to be merged after the Diet passed reform legislation Tuesday to rectify sharp gaps in the weight of votes among those constituencies.
In the first merger of Upper House electoral districts since World War II, the revised Public Offices Election Law will take effect before the next election in summer 2016.
The final bill, which came after several drafts and terse negotiations between parties, was submitted by the ruling Liberal Democratic Party and four opposition parties. It was passed by the Upper House last week before Tuesday’s approval by the Lower House.
The electoral reform will merge sparsely populated prefectures — Tottori, Shimane, Kochi and Tokushima — into two single districts. It will also cut two seats each from Miyagi, Niigata and Nagano, and add two seats each to Tokyo, Hokkaido, Aichi, Hyogo and Fukuoka.
While keeping the total number of Upper House seats unchanged at 242, the reform will narrow the vote weight disparity between the most and least populated constituencies to 2.97 to 1 from 4.77 to 1 in the previous Upper House election in July 2013, which the Supreme Court found last year to be “in a state of unconstitutionality.” The court called for fundamental reform of the electoral system.
Upper House elections take place every three years to elect half of the 242 lawmakers for six-year terms.
The law also stipulates that a conclusion will be reached on fundamental electoral reform toward the 2019 Upper House election to further narrow the vote-weight discrepancies.
Komeito and the opposition Democratic Party of Japan opposed the bill, arguing the vote-value gap should be trimmed to a ratio of less than 2 to 1.
Last week, DPJ President Katsuya Okada said he believes the reform plan could still be ruled as unconstitutional.
Some LDP members have also railed against the reform, with six members in districts affected by the changes walking out in protest before the Upper House vote last Friday.