A group of lawyers filed lawsuits across the nation on July 11 seeking to nullify results from the latest Upper House election, arguing that a flaw in the electoral system produced unfair outcomes in some locations.
The lawyers filed lawsuits with 14 high courts and their branches, arguing that carrying out the vote despite glaring disparities in the vote weight between certain districts violates the Constitution, which provides for the equal value of votes.
“Lawmakers who won an election held without correcting the disparity in the value of a single vote are not qualified to be in the Diet,” lawyer Hidetoshi Masunaga said at a news conference after the lawsuits were filed.
The suits argue that certain electoral districts had up to threefold vote-weight disparities, thereby distorting representation in the Diet. In other words, a vote cast in certain less populous districts counts for significantly more than if it were instead cast in another more populous part of the country.
The Fukui electoral district had the fewest eligible voters while the Kanagawa district had the most per Upper House member, according to the internal affairs ministry.
The disparity in the value of a single vote between them is 3.03-fold.
That means the value of a single vote in the Kanagawa district was worth only 33 percent of a vote in the Fukui district.
The Supreme Court concluded after Upper House elections in 2010 and 2013 that a maximum vote-weight disparity of around 5 times was “in a state of unconstitutionality.”
In response to the rulings, the Diet combined the electoral districts of Tottori and Shimane prefectures and those of Tokushima and Kochi prefectures ahead of the Upper House election in 2016.
But other areas subject to this problem have not followed suit, as many prefectures have put up resistance against combining electoral districts.
Currently, the largest vote-disparity gap is around threefold.