Three high courts in separate rulings Friday questioned the constitutionality of the disparity of up to five times in the weight of votes cast in different districts in last July's Upper House election.
Presiding Judge Tamio Hirota of the Fukuoka High Court ruled that the fivefold disparity in the weight of votes in the election represented "a violation of the Constitution."
Hirota blamed the current system of dividing the nation into electoral districts by prefecture rather than population and said the disparities in the weight of votes "are currently in an intolerable situation."
The ruling was on one of a series of lawsuits contesting the voting power disparity filed at all eight high courts and their six branches nationwide.
Acting on similar legal challenges, the Osaka High Court and the Miyazaki branch of the Fukuoka High Court ruled that the disparity in the weight of votes was in a "state of unconstitutionality."
On similar suits, a Tokyo High Court panel of judges and the Takamatsu High Court have determined the Upper House poll ran counter to the Constitution due to the fivefold disparity in the weight of votes, while seven panels at other high courts, including in Sendai and Hiroshima, have ruled the disparity was in a "state of unconstitutionality," while another panel at the Tokyo High Court has determined the disparity to be constitutional.
In the election, the number of eligible voters per Upper House seat in the most populous electoral district — Kanagawa Prefecture — was five times higher than that in Tottori Prefecture, the smallest district.