The recent Takamatsu High Court decision that the gap in the value of votes in the Upper House election in July was "in a state of unconstitutionality" challenges the Diet to fulfill its overdue promise to fundamentally overhaul the chamber's electoral system. While this was only the first in a series of rulings expected on more than a dozen lawsuits filed across the country over the last election, the Takamatsu court's decision that the maximum disparity of 3 to 1 in vote values was "impermissible under common sense" must be taken seriously.
Disparities in the value of votes between electoral districts emerge due to differences in the number of eligible voters per Diet seat allocated to districts. A ballot cast by a voter in a less-populous constituency carries more weight in electing a lawmaker than a vote in a more populous district if the same number of seats are allocated to both constituencies. The disparity is a grave issue that deviates from equality under the law and threatens to distort the representation of popular will in the Diet.
The Takamatsu court ruled that the disparity in the latest Upper House election was unacceptable given that the gap was within 2 to 1 in the last Lower House election in 2017. There are no justifiable excuses for lawmakers to further delay an overhaul of the Upper House electoral system to fundamentally address the problem.