Japan's Supreme Court on Wednesday ruled the vote disparity of up to 2.08-fold in the 2021 lower house election was constitutional.
The top court decision followed 16 conflicting rulings from lower courts, with plaintiffs demanding that the outcome of the House of Representatives election held on Oct. 31, 2021, be nullified.
Among the 15 justices of the top court's Grand Bench, 14 ruled the 2021 lower house election as constitutional, while one said it was unconstitutional.
Wednesday's ruling, which recognized parliament's efforts made in recent years to redress a vote disparity, was the second consecutive Supreme Court ruling that found a vote gap was constitutional, following the 2018 ruling on the 1.98-fold disparity in the 2017 lower house election.
Two groups of lawyers had filed the 16 lawsuits. Out of them, nine rulings said the gap was constitutional, while seven others said the election was held "in a state of unconstitutionality." None of them favored the plaintiffs' demand to nullify the election result.
The ruling pointed out that the more than 2-fold gap was caused by population movement, saying the disparity "will be corrected by a systematic framework adjustment based on the review of seat allocations every 10 years."
The Diet decided in 2016 to introduce a seat apportionment method to more accurately reflect population differences between prefectures by using national censuses.
Last November, the parliament also enacted a law bringing about the country's largest-ever change to the boundaries and distribution of lower house single-seat constituencies to correct a vote-value disparity.
The law was aimed at narrowing the vote disparity below the 2-fold level between densely and sparsely populated districts within the country.
Based on the national census conducted in 2020, the seat apportionment method would bring down the maximum vote-value disparity to 1.999-fold.
Following the ruling, Makoto Ito, one of the lawyers who had filed the lawsuits, told journalists, "The election system, which is at the root of the people's sovereignty, is distorted, and it needs to be fixed as quickly as possible. Parliament needs to think upon the ruling with sincerity."
In his opinion, Katsuya Uga, the sole justice who found the case unconstitutional, also pointed to the need for change. "It is necessary to design a system where the default is that there is no vote disparity," he stated.
The Supreme Court had ruled the lower house elections of 2009, 2012 and 2014, where the vote disparity was above 2.0-fold, were constitutionally problematic, saying they were in a state of unconstitutionality.