The 2016 Democratic Party leadership election was held on 15 September 2016 in accordance with the end of the presidential term which had commenced in March. It was the first full presidential election since the formation of the party from the merger of the Democratic Party of Japan and the Japan Innovation Party earlier in the year. Incumbent president Katsuya Okada chose not to run for re-election.
Party vice president Renhà  won in a landslide with 59% of the available points, defeating former president Seiji Maehara and newcomer Yuichiro Tamaki. She became the first female leader of the party and the second female opposition leader in Japan after Takako Doi, as well as the first mixed-race leader of a Japanese political party.
Katsuya Okada was elected president of the Democratic Party of Japan (DPJ) in January 2015 following the party's failure in the 2014 Japanese general election. Following the election, there was widespread discussion about a possible merger between the DPJ and Japan Innovation Party (JIP) in order to compete more effectively against the Liberal DemocraticâÂÂKomeito government of Shinzo Abe. However, the JIP was controlled by an Osaka-based faction led by the city's conservative mayor Tà Âru Hashimoto, who favoured cooperation with the government. In May, following the failure of Hashimoto's key political project, the Osaka Metropolis plan, the party leadership resigned and the pro-opposition faction gained the upper hand with Yorihisa Matsuno as new leader. In late August, Hashimoto and many of his Osaka-based allies resigned from the JIP to form a new Osaka-based party. Following this, Matsuno actively pursued a DPJâÂÂJIP merger, supported by most of the DPJ, particularly its right-wing. A merger was approved in February 2016 and took place on 27 March, forming the Minshintà  (Democratic Progressive Party), officially the Democratic Party in English.
Okada was elected as party president during the merger, with his term set to expire in September. He led the Democratic Party into the July upper house elections. The party won 32 seats, a net loss of 19 from their pre-election numbers. Okada also failed in his stated goal of denying pro-constitutional reform parties a two-thirds majority in the chamber, despite forging an electoral alliance with the Communist, Social Democratic, and People's Life parties. He stated he would serve out the remaining two months of his term, but that he had not decided whether to seek re-election. On 30 July, he announced that he would not run for another term.
The contest was originally scheduled for 7 September, but the party executive announced on 28 July that it would be pushed back by a week for administrative reasons.
The election was conducted via a points system:
In order to win, a candidate must secure more than 50% of points. If no candidate won more than 50%, a runoff was to be held the same day. In the runoff, only Diet members and approved candidates could vote.
Renhà  was the first candidate to announce her bid on 5 August. At the time of the contest, she was vice president of the DP and one of its most high-profile female politicians, known for her wit and public speaking talent. In the House of Councillors election prior to the contest, she was re-elected in Tokyo with 1.12 million votes, the most of any candidate in the country. She was considered the frontrunner and believed to be favoured by the outgoing leadership; there was speculation that she might be unopposed. She offered generational change and a fresh image, pledging to demonstrate to voters that the party had robust policies and could do more than just criticise the government. She advocated cutting investment in public works, reforming the tax system, and investing in childcare and a national scholarship program. Emphasising her personality, she contrasted herself with outgoing president Okada, who she playfully described as "a very boring man". Her candidacy was observed to be part of an increasing trend of female leadership in Japanese politics, alongside Yuriko Koike's election as Governor of Tokyo; Renhà  stated she wanted to inspire women to break the glass ceiling.
Seiji Maehara announced his candidacy on 26 August. He was a party veteran and previously served as president from 2005âÂÂ06 and foreign minister during 2010âÂÂ11. A leader of the party's right wing, he called for an end to the electoral pact with the Communist Party. He advocated free access to preschool and tertiary education, funded by increased taxes. Known as a longtime advocate of constitutional revision, Maehara softened his stance during the campaign, criticising Shinzo Abe's approach to the issue as divisive. In response to arguments that the party needed a new face, he stated that "freshness alone isnâÂÂt enough" and emphasised his experience with the failures of the DPJ's period in government from 2009 to 2012: "We need to take a moment to grovel and apologize to voters. That's a start."
Yuichiro Tamaki was a late entrant and began gathering sponsors from late August. On the eve of nominations, he said he was still "one or two short" of the 20 nominations required to stand, but was able to reach the threshold the following day. He was a third-term Diet member and his candidacy was supported by fellow junior legislators. He stated that "unless a person like me displays an all-out effort to revolutionize the party, the public will never understand how serious the DP is about changing itself."
Former lawmakers of the JIP, the largest single group within the Democratic Party, sought a united position in the contest. Former JIP president Kenji Eda considered running, but stated on 30 August that he would not due to lack of consensus within the group. Legislators were divided between Renhà Â, Maehara, and Tamaki. The following day, a group of eighteen ex-JIP members jointly endorsed both Renhà  and Maehara.
Goshi Hosono, who was narrowly defeated by Okada in the 2015 presidential contest, was considered a possible candidate. After discussions with Renhà Â, he announced on 9 August that he would not run and endorsed her.
Akira Nagatsuma aimed to run again, but ruled himself out on the 19th after failing to secure backing from the Akamatsu faction. Akihisa Nagashima announced his withdrawal from the contest on 30 August due to lack of support. Kazuhiro Haraguchi, who founded his own study group after the House of Councillors elections, aimed to run. He and Tamaki attempted to negotiate to unify their candidacies, but were unsuccessful; Haraguchi failed to gather the necessary sponsors.
Renhà  was the frontrunner and received widespread factional support. This included "mainstream" representatives in the outgoing executive, including outgoing president Okada. The Noda faction, Goshi Hosono's faction, the former JSP faction around Hirotaka Akamatsu, and Yoshiaki Takaki's faction of former DSP members all backed her, as did several former JIP members.
Maehara faced difficulty reaching 20 nominations due to overlapping membership inside his own faction, strong desire for new leadership within the party, and lack of unified support from the party right. He only chose to run after receiving encouragement from Michihiko Kano and securing support from Kano's former faction, now led by Akihiro Ohata. Maehara also attempted unsuccessfully to win over Akamatsu. These approaches to left-leaning factions were viewed as a pivot to the centre to counter widespread support for Renhà  throughout the party. After Akihisa Nagashima dropped out of the contest, his faction supported Maehara. He also reached out to former JIP members who were opposed to an uncontested race.
Tamaki was supported by former JIP members such as Masato Imai, as well as the Kan faction and parts of the Ohata faction.
A Sankei Shimbun-FNN poll of possible candidates on 8 August, when only Renhà  had announced her bid, found she was well ahead of all others with 32% support. Maehara garnered 7.5% support, Goshi Hosono 6.9%, Yukio Edano 6.8%, outgoing president Okada 4.3%, Akira Nagatsuma 3.3%, and Tamaki 1.4%. A 3âÂÂ4 September Mainichi Shimbun poll showed Renhà  at 32%, Maehara on 19%, and Tamaki on 4% among the general public. Among DP supporters, she had an overwhelming lead of 61% to Maehara's 20% and Tamaki's 7%.
A Sankei survey on 8 September indicated that Renhà  was well ahead of the other candidates and likely to win without the need for a runoff. They reported that her support totaled 65 out the party's 147 Diet members and a majority of its local assembly members. They attributed 40 supporters to Maehara, 20 to Tamaki, and 20 still undecided.
The issue of Renhà Â's nationality and citizenship emerged during the campaign. She was born to a Taiwanese father and Japanese mother, and was a Taiwanese citizen at birth, in accordance with Japanese citizenship law at the time which preferred children adopt the father's nationality. After a change in the law in 1985, she acquired Japanese citizenship at age 17. She previously claimed that she had renounced Taiwanese citizenship at the same time, but admitted on 13 September that she had not. Japanese law prohibits dual citizenship above the age of 22, though nobody has ever been deprived of citizenship for this reason. Renhà  stated that her father had filed the paperwork for her and that she was unaware he had done so incorrectly. She pledged to renew her efforts to renounce her Taiwanese citizenship.
Renhà  won 503 points of 849 available, therefore winning outright without the need for a runoff. She was supported by 80 of the party's 147 Diet members (54%) and a clear majority of grassroots members (62%) and local assembly members (61%). Her support was less pronounced among the 118 approved Diet candidates, where she won 50 votes to Maehara's 44.
Among the party membership, Renhà  swept almost every prefecture, performing best in the Tà Âhoku and Chà «goku regions. Maehara and Tamaki both swept their home prefectures, Kyoto and Kagawa respectively. Tamaki also won Wakayama Prefecture, while Maehara narrowly beat Renhà  in Gifu, Kumamoto, and Tottori. Overall, Renhà  won 167 points, Maehara 52, and Tamaki 12.