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Japan’s Supreme Court Rules the 2025 Upper-House Election Was Held in an “Unconstitutional State”
By Maya Wilson
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Japan’s Supreme Court ruled Wednesday that the country’s July 2025 upper-house election was held in a “state of unconstitutionality” because of a disparity in the weight of votes across constituencies, while stopping short of invalidating the results. The judgment found that the gap between the most and least influential votes had reached as much as 3.13-fold, and warned that parliamentary efforts to correct the imbalance had stalled.
The ruling, delivered on November 11, marks the first time the Supreme Court has found an upper-house election in that condition since electoral boundaries were revised ahead of the 2016 contest. The court described the 3.13-fold disparity as difficult to ignore, according to Kyodo News and NHK World.
The justices dismissed requests to nullify the 2025 election results. The decision therefore recognises a constitutional problem with the distribution of voting power without overturning the outcome of the poll.
The case concerned the principle that each vote should carry broadly equal weight, despite differences in population between Japan’s electoral constituencies. When some constituencies have far fewer voters than others, a ballot cast in a less-populated area can carry greater influence in determining representation than one cast in a more populous area.
The maximum disparity in the July 20, 2025 election was 3.13 to one. That was wider than the 3.03-fold gap recorded in the 2022 upper-house election. The disparity had stood at 3.08-fold in 2016 and 3.00-fold in 2019, according to Kyodo.
The court’s criticism focused not only on the size of the imbalance but also on the lack of progress in addressing it. It said parliamentary efforts to reduce disparities had “stalled,” a pointed assessment of lawmakers’ responsibility for maintaining an electoral system in which votes do not carry equal weight nationwide.
The judgment followed 16 rulings by lower courts on challenges to the 2025 election. Eleven found the election unconstitutional, while five concluded that it was constitutional. The Supreme Court’s decision places the highest court on the side of those who found the disparity had crossed a constitutional threshold, while rejecting the remedy sought by those challenging the results.
The ruling also marks a departure from the Supreme Court’s treatment of the three preceding upper-house elections. The 2016, 2019 and 2022 contests were ruled constitutional, despite disparities of more than three to one in each election.
The 2016 election followed a change to constituency boundaries under a revision of electoral law. Two pairs of less-populated prefectures were merged into combined constituencies: Tottori with Shimane, and Tokushima with Kochi. The revised arrangements were introduced for the 2016 election. The latest ruling is the first Supreme Court upper-house election judgment finding a “state of unconstitutionality” since those mergers.
The court has used similar language in earlier election cases. It found the 2013 election was held in a “state of unconstitutionality” when the vote-weight disparity reached 4.77-fold. A comparable finding followed the 2010 election, when the gap was 5.00-fold.
Those earlier figures were substantially higher than the 3.13-fold disparity in 2025. But the latest judgment makes clear that the lower numerical gap did not end the constitutional concern, particularly as the court considered the lack of sufficient progress in reform.
The distinction between a finding of unconstitutionality and the nullification of an election is central to Wednesday’s outcome. The Supreme Court found the disparity constitutionally unacceptable but dismissed the requests to invalidate the results. The elected upper-house members therefore retain their seats under the ruling.
The decision leaves parliament facing renewed pressure to address the way representation is distributed among constituencies. The court’s description of reform efforts as stalled signals dissatisfaction with the pace of change, although the ruling, as reported by Kyodo and NHK, does not set out a new timetable for legislative action.
Japan’s top court has now identified the imbalance in the 2025 vote as a constitutional problem. Its refusal to cancel the election preserves the results, but its warning to lawmakers is unmistakable: the disparity remains, and the effort to correct it has not advanced far enough.
— Maya Wilson, World Desk
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