September 2010 Democratic Party of Japan leadership election

The September 2010 Democratic Party of Japan leadership election was held on 14 September 2010, in accordance with the end of the presidential term which had commenced in 2008. Incumbent president Naoto Kan, who was elected in June, sought a full term. He was challenged by former leader Ichirō Ozawa.^[1] Kan won by a comfortable margin of 721 points to Ozawa's 491, an unexpectedly clear victory.^[2][3][4]

Ichirō Ozawa was originally re-elected to a two-year term as president of the DPJ in September 2008, but resigned the following May amidst a corruption scandal. He was succeeded by Yukio Hatoyama, who formed a leadership "troika" with Ozawa and Naoto Kan. Ozawa was appointed deputy leader and head of election strategy, while Kan handled Diet affairs and public relations. The three led the party to a landslide victory in the August 2009 election, and Kan was appointed deputy prime minister while Ozawa became secretary-general, effectively running the party while Hatoyama and Kan focused on government. However, Hatoyama was forced to resign in June 2010 amid coalition conflicts, foreign policy blunder, and another corruption scandal surrounding Ozawa. The latter also resigned his post at the same time. Kan was chosen as Hatoyama's successor with support from most of the party's factions.^[2]

Kan distanced himself from Ozawa once in office, appointing critics Yukio Edano and Yoshito Sengoku to key leadership roles. He also adopted fiscally conservative positions, such as raising the consumption tax, which Ozawa opposed. Though relegated to the backbenches, Ozawa retained the loyalty of many members of the party and controlled its largest faction. Kan suffered a major setback in July when the government lost its majority in the upper house election, greatly damaging its ability to pass legislation.^[2] With the scheduled end of the presidential term approaching in September, Kan intended to seek re-election despite increasing criticism, particularly from Ozawa and his faction.^[5]

In mid-August, signs emerged of an alliance between Ozawa and former Prime Minister Hatoyama. With his support, Ozawa announced on the 26th that he would contest the election against Kan. By this time, the level of destabilisation within the government led to fears that the party could split. Hatoyama and Azuma Koshiishi thus attempted to mediate between Ozawa and Kan on the eve of nominations on the 31st. The former demanded the removal of Edano and Sengoku, which Kan refused to do; talks thus broke down and both forged on with their candidacies. After this, Hatoyama reiterated his support for Ozawa.^[5][6]

The election was conducted via a points system:^[7]

• Each of the party's members of the National Diet had a vote worth two points. (812 points total)
• Registered party members or supporters could vote via mail if they had been registered by 25 August. Each House of Representative constituency had one point, awarded to the most voted candidate in that constituency. (300 points total)
• Each of the party's members of local councils or prefectural assemblies could vote via mail. Points for this tier were awarded to candidates in proportion to votes won. (100 points total)

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 could vote.

The campaign revolved primarily around policy. Ozawa advocated adhering to the party's 2009 election manifesto, which promised tax cuts and investment in areas such as healthcare, education, and infrastructure under the slogan "putting people's lives first". Kan argued that a change in policy was necessary in light of the economic situation and Japan's large budget deficit, which he aimed to reduce by raising the consumption tax and reducing expenditure. Ozawa also faced significant criticism over his recurrent corruption scandals: at the time of the election, he was under investigation for financial misappropriation. Kan said of Ozawa: "his way of politics is based on financial strength and the large numbers in his group. It is deeply coloured by the principle of money and numbers." Kan ran on the slogan "clean and open politics", and called for corporate political donations to be banned, while Ozawa called only for making donations public.^[1][8]

An opinion poll published in The Asahi Shimbun found that 65 percent of the general public preferred Kan as prime minister compared to 17 percent for Ozawa. Among DPJ supporters, the results were 73 percent for Kan and 20 for Ozawa. The same poll also found approval of the Kan cabinet at 49 percent, an increase of 12 points from the previous month.^[9] Another poll in The Nikkei found 73 percent preferred Kan compared to 17 for Ozawa.^[10]

Despite public opinion strongly favouring Kan, he was not certain to win since the Diet caucus held the lion's share of voting power.^[4] Ozawa was believed to hold a narrow lead among the party's 412 legislators.^[9][10] Media attributed about 150 members to Ozawa's faction, in addition to sixty from Hatoyama's faction. Kan's backing was scattered between his own faction (~50 members) and those of Seiji Maehara (~40) and Yoshihiko Noda (~30).^[6][11] On the eve of the contest on the 13th, The Nikkei reported the Kan had the lead due to support from members and local assembly officials, while Ozawa was attempting to close the gap by winning over Diet members.^[12]

The announcement of the results was streamed online by TBS via Ustream. The event was viewed by 270,000 unique users, the highest traffic ever from Asia, indicating a high level of interest in the race.^[13]

• "2010 Democratic Party of Japan Presidential Election". DPJ Archive. Retrieved 30 October 2025.
• 政権迷走　菅対小沢・政治とカネ・失言 [The Administration's Stumbling Block: Kan vs. Ozawa, Politics, Money, and Gaffes]. NHK (video) (in Japanese). Japan. 2010. Retrieved 30 October 2025.