The inadequacy of an Upper House electoral reform proposal that the Liberal Democratic Party finally agreed to is evident given that even its partner in the ruling coalition, Komeito, refuses to endorse it. It compares poorly with a plan jointly proposed by Komeito and the No. 1 opposition Democratic Party of Japan to correct the sharp disparity in the value of votes between electoral districts.

After dragging its feet to come up with its own plan to cut the vote value gap in Upper House elections, the LDP recently agreed to a proposal initiated by Ishin no To (Japan Innovation Party) and three small opposition parties to cut two seats each from districts in Miyagi, Niigata and Nagano, add two seats each to districts in Hokkaido, Tokyo, Aichi, Hyogo and Fukuoka, and combine the constituencies of Shimane and Tottori, and Tokushima and Kochi, into single districts respectively. Despite the lack of endorsement by its ruling coalition partner, the LDP reportedly plans to table the plan in the Upper House soon, while Komeito and the DPJ appear set to separately submit their version to the Diet.

Last year, the Supreme Court ruled that the disparity in the value of votes in the last Upper House election in 2013 — when a vote cast in a constituency with the least population per Diet seat carried 4.77 times more weight in electing lawmakers than a vote in the district with the largest population per seat — was in a "state of unconstitutionality." To narrow such a huge gap in the vote value, the top court called for a fundamental overhaul of the electoral system, including changing the current prefecture-based electoral districts.