Background
The appellants sought to invalidate the proportional-representation portion of the regular House of Councillors election held on July 20, 2025. They argued that the Public Offices Election Act’s “special quota” system, under which political parties may give designated proportional-representation candidates priority over other candidates on their lists, violated Article 43(1) of Japan’s Constitution.
They also argued that the constituency election held on the same day was invalid because the Act’s allocation of seats among constituencies was unconstitutional, and that this alleged defect rendered the proportional-representation election invalid as well. The Tokyo High Court rejected the challenge, and the appellants appealed to the Supreme Court.
The Court’s Holding
The Supreme Court unanimously dismissed the appeal and ordered the appellants to bear the appellate costs. It held that the statutory provisions establishing the special-quota system for the House of Councillors’ proportional-representation election do not violate Article 43(1) or other constitutional provisions. The Court said that conclusion followed from, or was clear in light of, its Grand Bench judgments of November 10, 1999, and January 14, 2004.
The Court further held that litigants seeking to invalidate the proportional-representation election may not challenge the constitutionality of the separate electoral system governing constituency-elected members. It therefore affirmed the Tokyo High Court’s reasoning and rejected both principal grounds of appeal. The remaining grounds did not qualify as permissible grounds for a final appeal under Article 312(1) or (2) of the Code of Civil Procedure.
Key Takeaways
- The House of Councillors’ special-quota system for proportional-representation candidates is constitutional.
- A suit challenging the proportional-representation election cannot be used to contest the constitutionality of the separate constituency-election system.
- The Supreme Court unanimously affirmed the Tokyo High Court and dismissed the election-invalidity appeal.
Why It Matters
The decision confirms that political parties may continue using the statutory special quota to prioritize designated candidates in House of Councillors proportional elections. It also reinforces a procedural boundary between challenges to the proportional-representation election and challenges to constituency elections, even when both are conducted on the same day.