How Japan Appoints a Prime Minister After Lower House Election; Will a Runoff Vote be Needed Without a Ruling Majority?

Yomiuri Shimbun file photo
The National Diet Building

After a House of Representatives election, a Prime Minister is appointed in a scheduled special Diet session through an election among members of the House of Representatives and an election among members of the House of Councillors. In these appointment elections, members vote for the leaders of their affiliated party or coalition.

Typically, if the ruling party holds a majority, the Prime Minister is decided in the first round of voting.

The rule of the House of Representatives states that if no candidate obtains a majority in the initial vote, a runoff will be conducted between the top two candidates. There have been four instances of runoff elections in the lower house.

For example, in 1979, due to a power struggle within the Liberal Democratic Party, a runoff was held between Masayoshi Ohira and Takeo Fukuda, with Ohira winning by a margin of 17 votes. In 1994, a contest was held between Tomiichi Murayama — backed by the LDP, the Japan Socialist Party, and the New Party Sakigake — and Toshiki Kaifu — supported by the Japan Renewal Party and Komeito — resulting in Murayama’s victory.

If the appointments by the House of Representatives and the House of Councillors differ, a joint committee is convened. If the two houses still cannot agree, the Constitution stipulates that the House of Representatives’ choice takes precedence.