Reiwa 7 (Gyo-Ke) No. 9 Election Invalidation Case

Following the July 28, 2025 House of Councillors election, attorney Hidetoshi Masunaga and other voters filed a lawsuit (Reiwa 7 (Gyo-Ke) No. 9) seeking invalidation of the election. They argued that the maximum vote weight disparity between the most and least populated districts violated the constitutional guarantee of equality. The Tokyo High Court heard the case, examining whether the disparity, which stood at approximately 3.0 to 1, exceeded permissible limits. The court applied the Supreme Court's prior standards and determined that the disparity was not in a state of unconstitutional inequality. The request was dismissed, maintaining the election results.

The Tokyo High Court dismissed the plaintiffs' claim, ruling that the disparity remained within constitutional bounds and that the election was valid.

Whether the vote weight disparity in the 2025 upper house election reached a level of unconstitutional inequality, warranting election invalidation.

The ruling reaffirmed judicial tolerance of certain vote weight disparities, continuing the pattern of previous Supreme Court decisions. It drew public attention to electoral system reform, with critics calling for legislative action to further reduce disparities, while supporters viewed the decision as maintaining electoral stability.