The Supreme Court has ruled that vote-value disparities in the July 2019 House of Councillors election, in which the weight of individual votes in less populated constituencies was up to three times those in more densely populated electoral districts, was constitutional.
Efforts to rectify the disparities in the summer poll through electoral system reforms went no further than changing the number of seats available in the Saitama Prefecture constituency, which has only a marginal effect on narrowing vote-value gaps.
And yet, the Supreme Court ruling has looked favorably on the Diet's choice to maintain mergers of neighboring prefectural constituencies and continue pursuing the same methods to reduce vote-value disparities.
In the 2016 upper house election, neighboring prefectural constituencies in Tottori and Shimane, and in Tokushima and Kochi, were each merged into single constituencies for the first time. Because of these moves, the maximum vote-value disparity between the most and least populated constituencies in the country fell to 3.08. As a result, the top court concluded that the vote-weight gap was "no longer in an unconstitutional state."
The Public Offices Election Act's supplementary clause which set the framework for the 2016 election also stipulated a fundamental reform of the electoral system and that a conclusion must be reached ahead of the 2019 election.
The latest top court ruling acknowledged that there was no major progress in the Diet's efforts, but it showed consideration to the legislature by stating that electoral reform takes time.
But four of the Supreme Court's 15 justices trying the case enclosed their opinions, including ones that had viewed the vote-value disparities in the 2019 upper house election as "in a state of unconstitutionality" or even "unconstitutional." One of the justices asserted that the national legislature's efforts to rectify vote weight gaps were utterly insufficient.
The original aim of electoral system reform done ahead of the 2019 upper house contest was to serve the ruling Liberal Democratic Party (LDP)'s own interests. In a bid to bail out its candidates being cast from their home constituencies due to the electoral zone mergers, a special quota giving them priority in winning proportional representation seats was set up by adding four more seats filled using the system.
The increase in the number of upper house seats, including the two in the Saitama constituency, was also designed to appease other parties. The moves are a far cry from fundamental electoral reform.
The constituency mergers have also had negative effects. In last summer's upper house poll, three of the four prefectures subject to the mergers registered record-low turnout.
Japan continues to see its major city populations become over concentrated while regional areas empty. As long as the current system of drawing electoral districts by prefecture is maintained, the vote-value disparities would only be left widening.
In recent years, the Supreme Court has called for correcting this system. But introducing more merged constituencies has its own limits. Unless the Diet carries out fundamental reform, the vote-value gaps in coming elections could be ruled again as in a state of unconstitutionality.
First and foremost, the Diet should discuss the future shape of the House of Councillors. As a chamber for careful deliberations whose members are given long terms without the threat of dissolution, the upper house needs to define more clearly its raison d'etre and role-sharing with the House of Representatives.
One of the four items for constitutional revision the LDP has proposed is having at least one upper house member elected from each of Japan's 47 prefectures. But if they are going to talk about constitutional amendment, they should first question how the upper chamber should stand.
Lawmakers must not procrastinate over discussion toward fundamental electoral reform by getting complacent because the top court has declared the vote weight gaps in the last upper house election constitutional.