The Japanese Supreme Court has decided to hear a case concerning the disparity in the value of votes in the House of Councillors election, which had a maximum discrepancy of 3.13 times among constituencies during the July 2022 elections. The votes' inequality, which violates the constitutional principle of equal vote value, has been challenged in numerous lawsuits filed by legal groups across the country. All 15 judges of the Supreme Court's Grand Bench are expected to issue a unified ruling within the year to determine whether this discrepancy constitutes a violation of the Constitution.

In the controversial election, the constituency with the highest number of voters per representative, Kanagawa, had over three times the number compared to the least populated constituency, Fukui, leading to significant inequalities in vote representation. While lower courts have categorized the government's efforts at correcting this electoral disparity as 'on the brink of unconstitutionality,' the ruling has been mixed; with some courts affirming the current system as constitutional, but emphasizing the urgent need for reform action by the National Diet (Japan's bicameral legislature).

The Supreme Court previously recognized a maximum disparity of 3.03 times in the preceding elections as constitutional yet urged the National Diet to correct these discrepancies. However, with little progress made on reform before the recent election, the latest court decisions anticipate ongoing scrutiny of legislative inaction. Some High Court judges have suggested that failure to address these disparities by the next election in 2028 may lead to a formal declaration of unconstitutionality, highlighting the unnecessary delays in electoral fairness and representation reform in Japan.