The ruling Liberal Democratic Party has endorsed an electoral reform plan proposed by four opposition parties to reduce disparities in the weight of votes in Upper House elections, paving the way for district changes for next summer's race.
The plan calls for merging constituencies with a smaller number of voters to make the seat allocation more in proportion to the population.
This is in response to a ruling by the Supreme Court last November that the gap in the weight of votes in the July 2013 Upper House election — as high as 4.77-fold — meant the results were "in a state of unconstitutionality."
As the LDP and the four opposition parties, including Ishin no To (Japan Innovation Party) and Jisedai no To (Party for Future Generations), have a majority in the upper chamber, a bill to carry out the reform could be enacted as soon as this month.
But even if the plan is realized, the disparity in the number of eligible voters per Upper House member elected would only narrow to 2.97 times between a constituency with the most voters and the one with the fewest, based on the 2010 census.
According to resident registration data as of Jan. 1, the vote value gap would reach 3.02 times even with the reform.
The reform plan calls for a merger of prefectural constituencies in Tottori and Shimane, and Kochi and Tokushima. At present, each of the 47 prefectures is a constituency, and they are represented by at least two Upper House members.
Upper House lawmakers serve six-year terms. Elections are held every three years for half the 242 seats. Winners in 47 prefectural districts fill 146 seats, while 96 members are elected under the nationwide party-list proportional representation system.