Review lower house constituencies based on changes in population

It is important to correct vote-value disparities by reallocating seats to reflect changes in the population. An appropriate review must be carried out based on a new method of allocating seats.

Preliminary figures from the 2020 census have been released. It has become clear that the population is concentrated in large cities, while the decline in rural areas is accelerating.

The population per member of the House of Representatives was 2.094 times greater in the Tokyo No. 22 Constituency, the most populous constituency, than in Tottori No. 2, the least populous. In 20 constituencies, the gap was at least double.

The 2017 lower house election implemented a so-called “zero increases, six decreases” corrective measure to reduce the number of seats in six prefectures, but subsequent population changes have widened the gaps again. The increasing disparity can be said to corroborate that there are limits to the stable operation of the current electoral system, even with a series of makeshift measures.

As part of legal revisions in 2016, the Diet decided to introduce the Adams’ method, which allocates a number of seats in each prefecture according to its population. This approach is relatively more generous to less populated prefectures than other methods.

There is great significance to determining the number of seats based on objective rules.

The lower house constituencies will have to be drastically redistributed in a formula of “10 increases, 10 decreases.” This will be the first time in 20 years that seats are drastically reallocated in a way that affects all prefectures. The current inversion in which Kanagawa Prefecture, the second most populous prefecture, has fewer seats than Osaka Prefecture, the third most populous, will be also resolved.

A government council will compile a plan to rezone constituencies, which will be applied to lower house elections from 2022 on.

In Tokyo, where the number of seats will increase by five, and other such prefectures, the number of municipalities that will be divided into multiple electoral constituencies may further increase. To avoid confusion among voters, such subdivisions should be kept to a minimum.

In 10 prefectures, including Miyagi, Fukushima, Wakayama and Yamaguchi, the number of seats will be reduced by one, forcing political parties to make difficult adjustments to their candidates. As the number of Diet members from the prefecture decreases, complaints that it will be harder for local voices to reach the national government may grow stronger.

What kind of election system is appropriate to accurately reflect the will of the people in the face of a declining population? It is important to discuss this issue comprehensively, including the division of roles between the House of Representatives and the House of Councillors. One option for the upper house is to strengthen its character as representatives of prefectures on condition of reducing its authority.

The largest vote-value disparity in upper house elections is 3.026 to one. The parties should discuss the issue at the council for the reform of the upper house election system and reach a conclusion as soon as possible.

There are strong calls for cutting seats, but it is not always desirable to reduce the number of lawmakers who represent the people. Rather, the reality is that decreasing the number of seats has made it more difficult to correct the disparities.

To strengthen the administrative oversight and legislative functions of the Diet, increasing the number of seats of constituencies may also be worth considering.

— The original Japanese article appeared in The Yomiuri Shimbun on June 27, 2021.