2023.01.25

2022 (Gyo-Tsu) 130

(Civil Case) Judgment concerning the case in which the court ruled that it cannot be said that the demarcation of constituencies for members of the House of Representatives to be elected from single-seat constituencies as provided in Article 13, paragraph (1) and Appended Table 1 of the Public Offices Election Act (prior to amendment by Act No. 89 of 2022) was in a state contrary to the constitutional requirement of equality in the value of votes at the time of the general election of members of the House of Representatives held on October 31, 2021 and that the aforementioned provisions cannot be found to be in violation of Article 14, paragraph (1) or other provisions of the Constitution

Case seeking invalidation of an election

Judgment of the Grand Bench, dismissed

Tokyo High Court, Judgment of February 14, 2022

The final appeal is dismissed.

The costs of the final appeal shall be borne by the appellants of final appeal.

Concerning the reasons for final appeal stated by the appellants who are also the counsel for final appeal, YAMAGUCHI Kuniaki, KUNIBE Toru, and MISAO Michihiko

1. This case is a suit to seek invalidation of an election that was filed by the appellants, who are voters in Tokyo 5th, 8th, 9th, and 18th Districts and Kanagawa 15th District in relation to the general election of members of the House of Representatives held on October 31, 2021 (hereinafter referred to as the "Election"), arguing that as the provisions on the demarcation of constituencies for an election of members of the House of Representatives to be elected from single-seat constituencies (hereinafter referred to as an "election in single-seat constituencies") are unconstitutional and thus invalid, elections in the aforementioned constituencies in the Election based on said provisions are also invalid.

2. The outline of facts lawfully determined by the court of prior instance is as follows.

(1) The Public Offices Election Act adopts the combination of single-seat constituencies and proportional representation as the election system for members of the House of Representatives, and it provides that the constant number of seats of members of the House of Representatives is 465, of which 289 are members to be elected from single-seat constituencies and 176 are members to be elected by proportional representation (Article 4, paragraph (1)). Regarding elections in single-seat constituencies, 289 constituencies are set up nationwide, and one member is to be elected from each constituency (Article 13, paragraph (1) and Appended Table 1 of the same Act; hereinafter these provisions throughout the period before and after the amendments mentioned later are collectively referred to as "provisions on demarcation"). Regarding an election of members to be elected by proportional representation (hereinafter referred to as an "election by proportional representation"), 11 constituencies are set up nationwide, and the predetermined number of members are to be elected in each constituency (Article 13, paragraph (2) and Appended Table 2 of the same Act). In a general election, elections in single-seat constituencies and an election by proportional representation are held simultaneously, and each voter is to have one vote in the elections in the relevant single-seat constituencies and the election by proportional representation, respectively (Articles 31 and 36 of the same Act).

Article 2 of the Act for Establishment of the Council on Demarcation of Constituencies for Members of the House of Representatives (hereinafter referred to as the "Act for Establishment of the Demarcation Council" throughout the period before and after the amendments mentioned later) provides that the Council on Demarcation of Constituencies for Members of the House of Representatives (hereinafter referred to as the "Demarcation Council") is to study and deliberate the revision of constituencies for members of the House of Representatives to be elected from single-seat constituencies and to prepare a draft revision of the constituencies (hereinafter merely referred to as a "draft revision") and recommend it to the Prime Minister when it finds necessary.

(2) Article 4 of the Act for Establishment of the Demarcation Council prior to amendment by Act No. 95 of 2012 (hereinafter referred to as the 2012 Amendment Act) (hereinafter the Act for Establishment of the Demarcation Council prior to the amendment is referred to as the "Former Act for Establishment of the Demarcation Council") provided as follows regarding recommendation of a draft revision by the Demarcation Council: [i] paragraph (1) provided that the Demarcation Council is to recommend a draft revision within one year from the date on which the population based on a population census implemented every decade pursuant to the provisions of the main clause of Article 5, paragraph (2) of the Statistics Act, (hereinafter referred to as a "large-scale population census") is first publicly notified in an official gazette; and [ii] paragraph (2) provided that notwithstanding the provisions of paragraph (1), the Demarcation Council may recommend a draft revision when it finds that there is an extreme imbalance in the population of each constituency or any other special circumstance. Article 3 of the Former Act for Establishment of the Demarcation Council provided as follows regarding the criteria for preparation of a draft revision (hereinafter referred to as the "criteria for demarcation" throughout the period before and after the amendments mentioned later): [i] paragraph (1) provided that the Demarcation Council must prepare a draft revision in a reasonable way in comprehensive consideration of circumstances, such as administrative districts, geographical features, and traffic, while basically keeping balance in population in each constituency and ensuring that the figure obtained by dividing population in the most populated constituency by population in the least populated constituency is less than 2; [ii] paragraph (2) provided that in preparing a draft revision, regarding the number of constituencies within the area of each prefecture, one constituency is to be apportioned to each prefecture in advance (hereinafter this rule is referred to as the "rule of reserving one seat per prefecture") and that the number of constituencies in a prefecture is to be the sum of the aforementioned one constituency apportioned in advance and the number of constituencies additionally apportioned to the prefecture in proportion to its population, out of the number that remains after deducting the number of prefectures from the number corresponding to the constant number of members to be elected from single-seat constituencies (hereinafter these criteria for demarcation are referred to as the "former criteria for demarcation").

The general election of members of the House of Representatives on August 30, 2009 (hereinafter referred to as the "2009 Election") was held based on the demarcation of constituencies specified under the provisions on demarcation prior to amendment by the 2012 Amendment Act (hereinafter referred to as the "former provisions on demarcation"). The maximum disparity between constituencies in terms of the number of voters on the same date was 2.304 to 1 (hereinafter all figures concerning disparity are approximate figures), and in 45 constituencies, the disparity compared to the constituency with the smallest number of voters was 2 to 1 or higher.

Regarding the 2009 Election, in 2010 (Gyo-Tsu) 207, the judgment of Grand Bench of the Supreme Court of March 23, 2011, Minshu Vol. 65, No. 2, at 755 (hereinafter referred to as the "2011 Grand Bench Judgment"), the court held as follows while evaluating Article 3, paragraph (1) of the Former Act for Establishment of the Demarcation Council as a reasonable criterion established with due consideration given to the requirement of equality in the value of votes: it is obvious that the rule of reserving one seat per prefecture became the major factor causing the expansion of the disparity between constituencies in terms of the value of votes at the time of the same election, and the rule of reserving one seat per prefecture that was introduced from the perspective of giving consideration to a sudden decrease in the constant number of seats to be apportioned to less populated regions should be considered to have already lost the reasonableness it had at the time of legislation; therefore, the part of the former criteria for demarcation which pertains to the rule of reserving one seat per prefecture, and demarcation of constituencies under the former provisions on demarcation as revised according to the same criteria had become contrary to the constitutional requirement of equality in the value of votes. The 2011 Grand Bench Judgment ruled that it cannot be said that no correction had been made to this state within a reasonable period of time as required by the Constitution and that the provisions on the former criteria for demarcation and the former provisions on demarcation cannot be found to be in violation of Article 14, paragraph (1) or other provisions of the Constitution. The same judgment then held that within a reasonable period of time as required for correction depending on the nature of the respective problems, legislative measures must be taken to meet the requirement of equality in the value of votes, such as abolishing as quickly as possible the rule of reserving one seat per prefecture, which is included in the former criteria for demarcation, and revising the former provisions on demarcation in line with the purport of Article 3, paragraph (1) of the Former Act for Establishment of the Demarcation Council.

(3) In response to the 2011 Grand Bench Judgment, the 2012 Amendment Act containing the deletion of Article 3, paragraph (2) of the Former Act for Establishment of the Demarcation Council and the reapportionment of constituencies involving no increase in any prefecture and decrease of one each in five prefectures (meaning a measure to decrease the number of constituencies in five prefectures with a small population per member by one without increasing the number of constituencies in any prefecture) was established on November 16, 2012. However, as the House of Representatives was dissolved on the same day, the general election of members of the House of Representatives on December 16, 2012 (hereinafter referred to as the "2012 Election") was held based on the demarcation of constituencies specified under the former provisions on demarcation in the same manner as for the 2009 Election.

Regarding the 2012 Election, in 2013 (Gyo-Tsu) 209, 210, and 211, the judgment of the Grand Bench of the Supreme Court of November 20, 2013, Minshu Vol. 67, No. 8, at 1503 (hereinafter referred to as the "2013 Grand Bench Judgment"), the court ruled as follows: the demarcation of constituencies that was specified under the former provisions on demarcation at the time of the same election was contrary to the constitutional requirement of equality in the value of votes as it had been at the time of the 2009 Election; yet, it cannot be said that no correction had been made within a reasonable period of time as required by the Constitution, and in conclusion, the former provisions on demarcation cannot be found to be in violation of Article 14, paragraph (1) or other provisions of the Constitution. The court then held that the Diet must continue constant efforts to develop an election system that is in line with the purport of Article 3 of the Act for Establishment of the Demarcation Council amended by the 2012 Amendment Act (provisions to the same effect as Article 3, paragraph (1) of the Former Act for Establishment of the Demarcation Council).

(4) In response to a recommendation made by the Demarcation Council based on the provisions of the Supplementary Provisions of the 2012 Amendment Act, on June 24, 2013, Act No. 68 of 2013 (hereinafter referred to as the "2013 Amendment Act") was established to revise the demarcation in 42 constituencies in 17 prefectures so that the disparity between constituencies in terms of population would be less than 2 to 1 on the premise of the reapportionment of constituencies involving no increase in any prefecture and decrease of one each in five prefectures. The provisions on demarcation were amended by the 2012 Amendment Act that was amended by the 2013 Amendment Act, and according to the result of the large-scale population census implemented in 2010, the maximum disparity between constituencies in terms of population was expected to be 1.998 to 1. However, on the very day of the general election of members of the House of Representatives held on December 14, 2014 (hereinafter referred to as the "2014 Election"), the maximum disparity between constituencies in terms of the number of voters was 2.129 to 1, and in 13 constituencies, the disparity compared to the constituency with the smallest number of voters was 2 to 1 or higher.

Regarding the 2014 Election, in 2015 (Gyo-Tsu) 253, the judgment of the Grand Bench of the Supreme Court of November 25, 2015, Minshu Vol. 69, No. 7, at 2035 (hereinafter referred to as the "2015 Grand Bench Judgment"), the court ruled as follows: the constant number of seats apportioned under the former criteria for demarcation was not reviewed with regard to prefectures other than those subject to the reduction in the constant number of seats through the aforementioned reapportionment of constituencies involving no increase in any prefecture and decrease of one each in five prefectures; and the major cause of occurrence of the aforementioned disparity in terms of the value of votes is the fact that in many prefectures, the constant numbers of seats actually apportioned were still different from the constant numbers of seats that should have been appointed to them as a result of the reapportionment of seats according to the criteria for demarcation after the deletion of Article 3, paragraph (2) of the Former Act for Establishment of the Demarcation Council, which was the provision that provided for the rule of preserving one seat per prefecture; the emergence of such disparity in terms of the value of votes should be described as the evidence of the fact that the development of an election system that is in whole in line with the purport of Article 3 of the Act for Establishment of the Demarcation Council amended by the 2012 Amendment Act cannot be deemed to have been achieved. The court then held that it must be concluded that the demarcation of constituencies revised by the 2012 Amendment Act amended by the 2013 Amendment Act remained in a state contrary to the constitutional requirement of equality in the value of votes. In the 2015 Grand Bench Judgment, the court ruled that as a realistic option that it may choose at its discretion, the Diet is deemed to be permitted to develop an election system in line with the purport of the same Article by repeating gradual reforms. The court then held as follows: taking into account circumstances, such as where the Diet has continued to review the election system even after the aforementioned revision of the demarcation of constituencies, the efforts made by the Diet to achieve correction from the time of the rendition of the 2011 Grand Bench Judgment until the 2014 Election cannot be said to be regarded as being unreasonable as an exercise of the legislative discretion; and it cannot be said that the Diet had failed to make correction within a reasonable period of time as required by the Constitution.

(5) Throughout the period before and after establishment of the 2013 Amendment Act, the Diet had continued discussions on the review, etc. of the election system to ensure that the future population changes will not lead to a state contrary to the constitutional requirement of equality in the value of votes. Since September 2014, the review of the system, etc. had been deliberated by the "Research Council on the Election System for the House of Representatives," which was established as an advisory body to the Speaker of the House of Representatives consisting of experts on this issue.

On January 14, 2016, the Research Council submitted an opinion to the Speaker of the House of Representatives. In the same opinion, the Research Council suggested, as a possible draft of review, the reduction of the constant number of seats of members of the House of Representatives by 10 to 465 (to reduce the constant number of seats of members to be elected from single-seat constituencies by 6 to 289, and reduce the constant number of seats of members to be elected by proportional representation by 4 to 176). Regarding correction of the disparity in terms of the value of votes, the Research Council cited the following as conditions to be satisfied by the method of apportionment of seats to each prefecture in elections in single-seat constituencies: seats are to be apportioned based on a proportional apportionment method; the disparity between prefectures in terms of the value of votes is to be kept as small as possible in order to lessen the disparity between constituencies in terms of the value of votes; changes in the numbers of seats apportioned to prefectures are to be small; and the apportionment method can also effectively function for a certain period in the future. As a result of examination in light of these conditions, the Research Council recommended the Adams' method (a method in which the sum of the figures obtained by dividing the population of each prefecture by a certain value and then rounding up the decimal places of the obtained quotients matches the constant number of seats in elections in single-seat constituencies) for the apportionment of seats to each prefecture. In the same opinion, the Research Council recommended that the review of apportionment of seats to each prefecture should be conducted based on population according to the result of a large-scale population census, which is implemented every decade, in consideration of the stability of the system. The Research Council also stated that if the disparity between constituencies in terms of population becomes 2 to 1 or higher in some constituencies based on a result of a population census implemented at the midpoint of the aforementioned decade, the Demarcation Council would review the demarcation of those constituencies to ensure that the aforementioned disparity remains less than 2 to 1 without changing the apportionment of seats to each prefecture.

(6) In response to the opinion mentioned in (5) above, Act No. 49 of 2016 (hereinafter referred to as the "2016 Amendment Act") was established on May 20, 2016. The same Act included reduction of the constant number of seats of members of the House of Representatives by 10 to 465 (the constant number of seats of members to be elected from single-seat constituencies was reduced by 6 to 289, and the constant number of seats of members to be elected by proportional representation was reduced by 4 to 176) and adoption of the Adams' method as a method of apportionment of seats to each prefecture.

Article 4 of the Act for Establishment of the Demarcation Council amended by the 2016 Amendment Act (hereinafter referred to as the "New Act for Establishment of the Demarcation Council") provides as follows regarding recommendation of a draft revision by the Demarcation Council: [i] paragraph (1) provides that the Demarcation Council is to recommend a draft revision within one year from the date on which population based on a large-scale population census implemented every decade in 2020 and thereafter, is first publicly notified in an official gazette; and [ii] paragraph (2) provides that notwithstanding the provisions of paragraph (1), if, regarding the population of the Japanese people in each constituency according to the result of a population census implemented in a year that falls under the fifth year from the year of the preceding large-scale population census implemented pursuant to the provisions of the proviso to Article 5, paragraph (2) of the Statistics Act (hereinafter referred to as a "simplified population census"), the figure obtained by dividing population in the most populated constituency by population in the least populated constituency is 2 or more, the Demarcation Council is to recommend a draft revision within one year from the date on which the population according to the result of said simplified population census is first publicly notified in an official gazette. Article 3 of the New Act for Establishment of the Demarcation Council provides as follows regarding the criteria for demarcation: [i] paragraph (1) provides that the Demarcation Council must prepare a draft revision in a reasonable way in comprehensive consideration of circumstances, such as administrative districts, geographical features, and traffic, while keeping balance in population (meaning the population of the Japanese people according to the result of a recent population census; the same applies hereinafter) in each constituency and ensuring that the figure obtained by dividing the population in the most populated constituency by the population in the least populated constituency is less than 2; [ii] paragraph (2) provides that in preparing a draft revision pertaining to a recommendation under the provisions of Article 4, paragraph (1) of the same Act, the number of constituencies within the area of each prefecture is to be the figure obtained by dividing the population of each prefecture by a criterion divisor for single-seat constituencies (meaning a divisor for which the sum of the figures obtained by dividing the population of each prefecture by that devisor [if a fraction less than 1 arises, the fraction is to be rounded up to 1] matches a figure corresponding to the constant number of seats of members to be elected from single-seat constituencies) (if a fraction less than 1 arises, the fraction is to be rounded up to 1) (Adams' method); [iii] and paragraph (3) provides that in preparing a draft revision pertaining to a recommendation under the provisions of Article 4, paragraph (2) of the same Act, the number of constituencies for members to be elected from single-seat constituencies in the area of each prefecture is not to be changed (hereinafter the mechanism for revision of constituencies under the aforementioned provisions, including these criteria for demarcation, is referred to as the "new demarcation system").

Furthermore, as a measure to correct the disparity in terms of the value of votes before the number of constituencies in each prefecture was changed by the Adams' method, Article 2, paragraph (1) of the Supplementary Provisions of the 2016 Amendment Act provided that notwithstanding the provisions of Article 4 of the New Act for Establishment of the Demarcation Council, the Demarcation Council would prepare and recommend a draft revision based on the result of a simplified population census implemented in 2015 (hereinafter referred to as the "2015 Population Census") on the premise of decreasing the constant number of seats of members to be elected from single-seat constituencies by 6. Article 2, paragraphs (2) and (3) of the same Supplementary Provisions provided as follows regarding preparation of the aforementioned draft revision: notwithstanding the provisions of Article 3 of the New Act for Establishment of the Demarcation Council, in relation to the number of constituencies in each prefecture, from the perspective of ensuring the stability of the election system through minimization of prefectures that are affected by changes in the number of constituencies, the Demarcation Council is to conduct the reapportionment of constituencies involving no increase in any prefecture and decrease of one each in six prefectures (meaning a measure in which, regarding prefectures for which the number of constituencies calculated by the Adams' method is less than the number of constituencies before the amendment based on the result of the 2015 Population Census, the number of constituencies is to be reduced by one each for six prefectures in ascending order according to the figure obtained by dividing the population of the prefecture by the number of constituencies calculated by the same method, and the number of constituencies before the amendment is maintained for the other prefectures), and prepares a draft revision in a reasonable way in comprehensive consideration of circumstances, such as administrative districts, geographical features, and traffic, while ensuring that the disparity between constituencies in terms of population according to the result of the 2015 Population Census is kept less than 2 to 1 and basically ensuring that the disparity between constituencies in terms of population based on expected population in 2020, the year when the next large-scale population census would be implemented, is less than 2 to 1 and keeping balance between the population in each constituency according to the result of the 2015 Population Census and expected population therein in 2020.

On April 19, 2017, the Demarcation Council recommended to the Prime Minister a draft revision including the revision of the demarcation in 97 constituencies in 19 prefectures on the premise of the reapportionment of constituencies involving no increase in any prefecture and decrease of one each in six prefectures. In response to this, Act No. 58 of 2017 (hereinafter referred to as the "2017 Amendment Act") was established on June 9, 2017, and provisions on demarcation were amended by the 2016 Amendment Act amended by the 2017 Amendment Act (hereinafter provisions on demarcation after the same amendment (prior to amendment by Act No. 89 of 2022) are referred to as the "Provisions on Demarcation," and the demarcation of constituencies specified under the Provisions on Demarcation are referred to as the "Demarcation of Constituencies").

(7) The House of Representatives was dissolved on September 28, 2017, and the general election of members of the House of Representatives was held on October 22, 2017 based on the Demarcation of Constituencies (hereinafter referred to as the "2017 Election"). With regard to the disparity between constituencies in terms of the number of voters on the very day of the 2017 Election, the disparity between the constituency with the largest number of voters (Tokyo 13th District) and the constituency with the smallest number of voters (Tottori 1st District) was 1.979 to 1, and there was no constituency for which disparity compared to the constituency with the smallest number of voters was 2 to 1 or higher.

In 2018 (Gyo-Tsu) 153, the judgment of the Grand Bench of the Supreme Court of December 19, 2018, Minshu Vol. 72, No. 6, at 1240 (hereinafter referred to as the "2018 Grand Bench Judgment"), the court ruled as follows: the Demarcation of Constituencies as of the 2017 Election reduced the maximum disparity between constituencies in terms of the number of voters, etc. by first implementing a legislative measure to considerably reduce the disparity between constituencies in terms of the value of votes through apportionment of seats to each prefecture by the Adams' method that uses a calculation proportional to population, and also to maintain such state in a stable manner, and then by conducting reappointment of constituencies involving no increase in any prefecture and decrease of one each in six prefectures and revising the demarcation of constituencies as measures to correct the disparity until seats are apportioned by the Adams' method; and the Demarcation of Constituencies can be evaluated as having achieved gradual correction from the viewpoint of ensuring the stability of the election system, while meeting the demand of securing equality in the value of votes. The 2018 Grand Bench Judgment thus held as follows: considering the content of legislative measure until the 2017 Amendment Act and the state of disparity that narrowed as a result, it cannot be said that the Demarcation of Constituencies was in a state contrary to the constitutional requirement of equality in the value of votes merely based on the fact that, there were prefectures in the 2019 Election for which the constant number of seats to be apportioned based on the former criteria for demarcation that included the rule of reserving one seat per prefecture was not changed and for which the number of seats actually apportioned differed from the constant number of seats to be apportioned if seats were apportioned to each prefecture by the Adams' method; and it can be said that development of an election system compliant with Article 3, paragraph (1) of the New Act for Establishment of the Demarcation Council had been achieved at the time of the 2017 Election; therefore, the revision of the demarcation of constituencies and other revisions by the 2016 Amendment Act and the 2017 Amendment Act should be considered a reasonable exercise of the discretion vested in the Diet, and the state contrary to the constitutional requirement of equality in the value of votes, which the 2015 Grand Bench Judgment indicated with regard to the demarcation of constituencies at the time of the 2014 Election, can be deemed to have been eliminated by the 2016 Amendment Act as amended by the 2017 Amendment Act; consequently, it cannot be said that the Demarcation of Constituencies was in a state contrary to the constitutional requirement of equality in the value of votes at the time of the 2017 Election.

(8) The House of Representatives was dissolved on October 14, 2021, and the Election was held on October 31, 2021 based on the Demarcation of Constituencies. Under the Demarcation of Constituencies, the maximum disparity between constituencies in terms of population was 2.096 to 1 based on the result of a large-scale population census implemented in 2020. With regard to the disparity between constituencies in terms of the number of voters on the very day of the Election, the disparity between the constituency with the largest number of voters (Tokyo 13th District) and the constituency with the smallest number of voters (Tottori 1st District) was 2.079 to 1, and in 29 constituencies, the disparity compared to the constituency with the smallest number of voters was 2 to 1 or higher.

3.(1) It is understood that the Constitution requires equality in the substance of the right to vote, or in other words, equality in the value of votes. On the other hand, equality in the value of votes is not the absolute criterion for determining the design of an election system, but it must be realized in a harmonized manner in relation to other policy purposes and grounds that the Diet is duly authorized to consider. The Constitution provides that the constant number of seats, the constituencies, the method of voting and other matters concerning elections of members of the respective Houses of the Diet shall be specified by law (Article 43, paragraph (2) and Article 47), thus allowing the Diet to have broad discretion to determine the design of the election system.

It should be said that in the case of adopting a system for holding an election of members of the House of Representatives by dividing the entire area of the country into a number of constituencies, the Constitution requires that securing equality in the number of voters or population per member to the greatest possible extent should be the most important and the essential criterion for determining the apportionment of seats and the demarcation of constituencies among all features of the design of an election system, but it is understood that the Constitution also allows the Diet to take other factors into consideration as long as it is reasonable to do so. When specifically establishing constituencies, it is required that municipalities or other administrative districts, which were created by subdividing prefectures, be used as basic units, and while taking into account various factors including the size, population density, composition of residents, transportation conditions, and geographical situations of the respective areas, that efforts be made to ensure that the will of the people will be reflected properly in the process of carrying out national politics; and at the same time, it is necessary to reconcile this with the requirement of securing equality in the value of votes. Consequently, determination as to the constitutionality of an election system is to be made by examining whether or not, even when all of these circumstances are comprehensively taken into account, the election system is justified as a reasonable exercise of the discretion vested in the Diet. Said features of the design of the election system specifically determined by the Diet should be judged to be unconstitutional only where these features run counter to said constitutional requirements, go beyond the bounds of the aforementioned discretion vested in the Diet even in consideration of such discretion, and are found unacceptable.

The reasoning presented above is in line with the purports of the series of Grand Bench judgments previously handed down regarding elections of members of the House of Representatives, starting from 1974 (Gyo-Tsu) 75, the judgment of the Grand Bench of the Supreme Court of April 14, 1976, Minshu Vol. 30, No. 3, at 223 (see the aforementioned judgment of the Grand Bench of the Supreme Court of April 14, 1976; 1981 (Gyo-Tsu) 57, the judgment of the Grand Bench of the Supreme Court of November 7, 1983, Minshu Vol. 37, No. 9, at 1243; 1984 (Gyo-Tsu) 339, the judgment of the Grand Bench of the Supreme Court of July 17, 1985, Minshu Vol. 39, No. 5, at 1100; 1991 (Gyo-Tsu) 111, the judgment of the Grand Bench of the Supreme Court of January 20, 1993, Minshu Vol. 47, No. 1, at 67; 1999 (Gyo-Tsu) 7, the judgment of the Grand Bench of the Supreme Court of November 10, 1999, Minshu Vol. 53, No. 8, at 1441; 1999 (Gyo-Tsu) 35, the judgment of the Grand Bench of the Supreme Court of November 10, 1999, Minshu Vol. 53, No. 8, at 1704; 2006 (Gyo-Tsu) 176, the judgment of the Grand Bench of the Supreme Court of June 13, 2007, Minshu Vol. 61, No. 4, at 1617; the 2011 Grand Bench Judgment; the 2013 Grand Bench Judgment; the 2015 Grand Bench Judgment; and the 2018 Grand Bench Judgment), and there is no need to modify it.

(2) Based on the aforementioned basic framework for determination, as mentioned in 2. (7) above, the 2018 Grand Bench Judgment evaluated the Demarcation of Constituencies at the time of the 2017 Election as having achieved gradual correction from the viewpoint of ensuring the stability of the election system, while meeting the demand of securing equality in the value of votes, based on the facts that: the new demarcation system was established to considerably reduce the disparity between constituencies in terms of the value of votes and to maintain such state in a stable manner; pursuant to the provisions of the Supplementary Provisions of the 2016 Amendment Act, the Demarcation of Constituencies was set so as to ensure that the disparity between constituencies in terms of population is kept less than 2 to 1 throughout five years until 2020, the year when the next large-scale population census would be implemented, on the premise of the reappointment of constituencies involving no increase in any prefecture and decrease of one each in six prefectures; and the maximum disparity between constituencies in terms of the number of voters on the very day of the same election was thereby reduced. The 2018 Grand Bench Judgment then held as follows: as the development of a reasonable election system consisting of the new demarcation system and the Demarcation of Constituencies had already been achieved in such manner, the state contrary to the constitutional requirement of equality in the value of votes can be deemed to have been eliminated even if there were prefectures for which apportionment of seats to each prefecture by the Adams' method had not been conducted and the constant number of seats to be apportioned based on the former criteria for demarcation that included the rule of reserving one seat per prefecture had not been changed and for which the number of seats actually apportioned differed from the constant number of seats to be apportioned if seats were apportioned to each prefecture by the Adams' method.

The Election was held based on the Demarcation of Constituencies in the same manner as for the 2017 Election. After that, no additional measure to correct the disparity was taken. As mentioned in 2. (8) above, at the time of the Election, the disparity between constituencies had become larger than that at the time of the 2017 Election, and the maximum disparity in terms of the number of voters was 2.079 to 1. However, under the new demarcation system, the disparity between constituencies in terms of the value of votes is to be corrected by conducting apportionment of seats to each prefecture by the Adams' method every decade in consideration of the stability of the election system, while naturally assuming that the disparity can expand due to subsequent population changes even if constituencies are revised. It can thus be said that the disparity that expanded under the Demarcation of Constituencies, which is in an integrated relationship with the new demarcation system, is also expected to be corrected within the framework of the new demarcation system. Such system is found to be reasonable as held in the 2018 Grand Bench Judgment, and even if the disparity expands under the Demarcation of Constituencies as mentioned above, it cannot be said that the situation led to a state contrary to the constitutional requirement of equality in the value of votes unless there are circumstances where the disparity should be considered to have expanded due to a new factor that is incompatible with the constitutional requirement of equality in the value of votes or where the degree of expansion of the disparity is so remarkable that the system becomes unreasonable.

Regarding the disparity between constituencies in terms of the value of votes at the time of the Election, there is no circumstance based on which the disparity expanded due to a factor other than natural population changes, and the degree of expansion cannot be considered to be remarkable. Therefore, it cannot be said, based on the aforementioned expansion of the disparity, that the Demarcation of Constituencies had been in a state contrary to the constitutional requirement of equality in the value of votes at the time of the Election.

(3) Therefore, it cannot be said that the Demarcation of Constituencies specified under the Provisions on Demarcation was in a state contrary to the constitutional requirement of equality in the value of votes at the time of the Election, and it thus cannot be said that the Provisions on Demarcation are in violation of Article 14, paragraph (1) or other provisions of the Constitution.

Incidentally, on the grounds of the first paragraph of the Preamble, Article 43, paragraph (1), or other provisions of the Constitution, the appellants also argue that under representative democracy, members of the House of Representatives need to be elected by the same population, respectively, and that the Election is invalid as it is contrary to that necessity. However, it is obvious from the above that the appellants' arguments are groundless.

4. For the reasons described above, the determination of the court of prior instance to the effect that it cannot be said that the Provisions on Demarcation were in violation of the Constitution at the time of the Election can be accepted. The appellants' arguments are not acceptable.

Accordingly, the Court unanimously decides as set forth in the main text of the judgment, except for the dissenting opinion stated by Justice UGA Katsuya.

The dissenting opinion stated by Justice UGA Katsuya is as follows.

1. As my opinion differs from the majority opinion on a point, I would like to state my opinion thereon.

I think that under the current Constitution, voters are not only formally granted the right to cast the same number of votes but also granted the right to vote with equal value in elections of members of the House of Representatives. Therefore, lawmakers must design an election system while considering a state without disparity in the value of one vote as the default. However, Article 47 of the Constitution provides that electoral districts, method of voting and other matters pertaining to the method of election of members of both Houses shall be fixed by law, and my opinion also does not differ from the majority opinion in that equality in the value of votes does not become the absolute criterion. That is, I also think that a state where the disparity is 1 to 1 cannot be completely realized because the right to vote also yields to constraints due to public welfare. However, lawmakers are accountable for the fact that inequality in the value of one vote is an inevitable constraint due to considerations made for public welfare, and if the disparity in terms of the value of votes is brought about by an unreasonable constraint, it must be considered to be unconstitutional. Even in my opinion, setting up of constituencies is permitted as a constraint due to public welfare as long as it is based on a reasonable ground even if it cannot make the value of one vote completely equal for all constituencies. This is because, compared to national constituency-based elections, elections using constituencies give an opportunity for voters to know more about candidates and because it is found to be reasonable that issues unique to each constituency become election issues and affect voting by voters. In the case of adopting an election system using constituencies, it is considered possible to take into account the districts of local public entities when setting the scope of each constituency unless it causes an impermissible disparity in the value of votes. In the case of setting up constituencies, it is also considered permissible to adopt a system in which provisions on demarcation are reviewed at reasonable intervals because of the fact that population transfers between constituencies naturally occur and that a certain period of time is required for the amendment of provisions on demarcation and from the perspective of demand of a stable election system.

However, it must be said that the Demarcation of Constituencies contained a part that was hard to recognize as a reasonable constraint from the perspective of public welfare. That is, the 2011 Grand Bench Judgment determined that the rule of reserving one seat per prefecture and the demarcation of constituencies based thereon were in an unconstitutional state. However, under the Demarcation of Constituencies, the constant number of seats to be apportioned based on the former criteria for demarcation that included the rule of reserving one seat per prefecture had not been changed in a considerable number of prefectures, and those prefectures included prefectures to which a different number of seats would have been apportioned if seats had been apportioned by the Adams' method based on the result of the 2015 Population Census. From my standpoint, it cannot be said that there are unavoidable circumstances to admit a disparity in the value of one vote in relation to the Demarcation of Constituencies, under which the constant number of seats to be apportioned based on the former criteria for demarcation that included the rule of reserving one seat per prefecture had not been changed in a considerable number of prefectures. Therefore, unlike the majority opinion in the 2018 Grand Bench Judgment, I think that the Demarcation of Constituencies at the time of the 2017 Election could not be considered to have eliminated an unconstitutional state. Thus, the Demarcation of Constituencies at the time of the Election, which was held after the amendment of the Public Offices Election Act without the Diet having taken any additional measure to correct the disparity, is also considered not to have gotten out of an unconstitutional state.

2. This Court examined this case according to the framework for determination consisting of the following: [i] whether the apportionment of seats or the demarcation of constituencies has reached a state contrary to the constitutional requirement of equality in the value of votes in relation to the disparity in terms of the value of votes; [ii] in the case where the apportionment of seats or the demarcation of constituencies has reached the aforementioned state, whether the provisions on the apportionment of seats or provisions on demarcation have come to violate the provisions of the Constitution as correction has not been made within a reasonable period of time as required by the Constitution; and [iii] in the case where the aforementioned provisions have come to violate the provisions of the Constitution, whether the court only declares illegality of the election without invalidating the election. This Court has explained that it had adopted the method of making a determination after going through these stages because of the relationship between judicial power and legislative power as predetermined by the Constitution. That is, even if the court determines that an election system has a constitutional problem from the perspective of equality in the value of votes, it per se cannot establish a specific alternative system and the system will be corrected through the Diet's legislation, and the Diet also has broad discretion to determine the method of correction and is expected to review the system at any stage of the aforementioned framework for determination; in other words, it is in line with the purport of the Constitution that the court expresses a certain determination at each stage of the aforementioned framework for determination concerning whether an election system conforms to the Constitution and that the Diet takes appropriate measures as required to correct the system in light of the court's determination (the 2013 Grand Bench Judgment and the 2015 Grand Bench Judgment).

Certainly, even if the court determines that an election system has a constitutional problem from the perspective of equality in the value of votes, it per se cannot establish a specific alternative system and the system will be corrected through the Diet's legislation. Even if the court holds that the election system is unconstitutional when it is in an unconstitutional state, the court would not establish a specific system and the method of correcting the system is still left to the Diet's legislation. Therefore, it is considered that the court's holding neither goes beyond the limits of judicial power as predetermined by the Constitution nor constitutes infringement of legislative power. There is the issue of whether it is permitted to invalidate an election system, as long as it is unconstitutional, even before the passage of a reasonable period of time, but this issue only needs to be examined as the issue of the effect of a judgment on unconstitutionality as mentioned in [iii] above, and seems not to become a reason for the necessity of the stage mentioned in [ii] above.

Therefore, matters that this Court considered in the theory of a reasonable period of time need to be examined in a case seeking compensation by the State when determining the presence or absence of negligence. However, in a case seeking invalidation of an election, it is safe to say that provisions on demarcation under the Public Offices Election Act are unconstitutional as long as the apportionment of seats or the demarcation of constituencies was objectively in an unconstitutional state at the time of an election.

If the Supreme Court, which has the right to examine unconstitutional legislation pursuant to Article 81 of the Constitution, renders a judgment that legislation is unconstitutional, the Diet has the obligation to respect the judgment pursuant to Article 99 of the Constitution. However, if the Supreme Court renders a judgment that legislation is in an unconstitutional state but is constitutional in the end, it is questionable whether it can be said that the judgment causes the Diet to have the obligation to eliminate an unconstitutional state though it virtually functions to give warning to encourage the Diet to eliminate the unconstitutional state.

3. According to my opinion mentioned above, the Election is, in principle, to be invalidated pursuant to Article 98, paragraph (1) of the Constitution as long as the Provisions on Demarcation are unconstitutional. However, a suit over the disparity in terms of the value of one vote under the provisions of Article 204 of the Public Offices Election Act is originally not a suit predetermined by the same Article; however, it is unreasonable if there is no judicial relief for the right to vote, which is a right that forms the basis of the sovereignty of the people; therefore, a suit for a basic right was substantially created as case law by formally using the provisions of the same Article. Therefore, regarding the way of a judgment, I think that it is exceptionally permitted to make a flexible determination in light of the division of roles between the judicial branch and the legislature, unlike in general suits.

After the 2011 Grand Bench Judgment, the provisions of Article 3, paragraph (2) of the Former Act for Establishment of the Demarcation Council, which stipulated the rule of reserving one seat per prefecture, were deleted by the 2012 Amendment Act, and the demarcation of constituencies was revised by the 2013 Amendment Act so as to ensure that the disparity between constituencies in terms of population is less than 2 to 1. In January 2016, in response to the opinion of the "Research Council on the Election System for the House of Representatives," the 2016 Amendment Act provided as follows: the Demarcation Council would recommend a draft revision in association with changes in the number of constituencies in each prefecture based on the Adams' method based on the result of a large-scale population census to be implemented every decade in 2020 and thereafter; and if there are constituencies between which the maximum disparity in terms of population is 2 to 1 or higher based on the result of a simplified population census to be implemented in the fifth year from the year of the preceding large-scale population census, the Demarcation Council would revise the demarcation of constituencies so as to ensure that the disparity is less than 2 to 1. In such manner, the next election of members of the House of Representatives is expected to be held based on the demarcation of constituencies from which the effect of the rule of reserving one seat per prefecture has been eliminated. Furthermore, in Article 5 of the Supplementary Provisions of the 2016 Amendment Act, the Diet proclaims that the manner of a desirable election to elect members of the Diet: who are representatives of all the people, needs to be constantly reviewed so as to ensure achievement of the purpose of fair and effective representation. The Diet should be valued for such series of efforts for reducing the disparity in terms of the value of votes though gradual action and for having proclaimed its intention to conduct constant review in the future. In light of these facts, I think that it is appropriate not to invalidate the Election but only to declare that the Election is illegal.

Justice TOKURA Saburo

Justice YAMAGUCHI Atsushi

Justice MIYAMA Takuya

Justice MIURA Mamoru

Justice KUSANO Koichi

Justice UGA Katsuya

Justice HAYASHI Michiharu

Justice OKAMURA Kazumi

Justice NAGAMINE Yasumasa

Justice YASUNAMI Ryosuke

Justice WATANABE Eriko

Justice OKA Masaaki

Justice SAKAI Toru

Justice IMASAKI Yukihiko

Justice OJIMA Akira