Reiwa 7 (Gyo-Ke) 2 Election Invalidity Lawsuit

Following the October 27, 2024, general election for the House of Representatives, a group of attorneys led by Hidetoshi Masunaga filed a lawsuit seeking to invalidate the election results. They argued that the maximum vote-value disparity of 2.06 between the least and most populous districts violated the principle of equality under Article 14 of the Constitution. The case was brought before the Tokyo High Court and subsequently appealed to the Supreme Court of Japan. In 2025, the Grand Bench of the Supreme Court, presided over by Chief Justice Yukihiko Imasaki, issued its ruling. The court acknowledged the continued existence of a considerable disparity but determined that the electoral system, including the current apportionment method, had not yet reached a state of unconstitutionality. The lawsuit was dismissed.

The Supreme Court's Grand Bench ruled that the election was constitutional and dismissed the appeal to invalidate the results. The court stated that the disparity had not reached a level requiring judicial intervention to nullify the election.

Whether the maximum vote-value disparity of 2.06 in the 2024 House of Representatives election violated the constitutional requirement of equality in voting value, necessitating the invalidation of the election.

The ruling reaffirmed the judiciary's reluctance to invalidate national elections over vote-weight disparities, placing the onus on the Diet for electoral reform. While upholding the election, the decision drew continued criticism from legal scholars and civic groups regarding the persistent inequality in representation, especially for voters in rural versus urban districts. It highlighted the ongoing tension between judicial restraint and the protection of fundamental democratic rights in Japan.