The Supreme Court's 15-member Grand Bench ruled March 23 that the vote-value disparity in the August 2009 Lower House election, which reached a maximum 2.30-to-1, was "in a state of unconstitutionality."
Although the Grand Bench did not explicitly say the disparity was "unconstitutional," it is the first such ruling by the Grand Bench since a combination of the single-seat constituency and proportional representation systems was introduced for Lower House elections in 1994. The ruling means that the Diet must quickly rectify the situation.
The Supreme Court ruling dealt with nine lawsuits filed by two groups of lawyers, who claimed that the disparity violates the constitutionally guaranteed equality before the law. In the 2009 Lower House election, in which the Democratic Party of Japan trounced the Liberal Democratic Party to become a governing party, the maximum vote-value disparity reached 2.30-to-1 between the Kochi No. 3 constituency (with the least number of voters) and the Chiba No. 4 constituency (with the largest number of voters). This means that a voter in the Chiba constituency had only about 0.4 of the vote value enjoyed by a Kochi constituent.