The 14th Democratic Party of Japan leadership election was held on 4 June 2010 after the incumbent party President Yukio Hatoyama resigned after failing to fulfil a promise to the voters regarding the United States Forces Japan's bases in Okinawa Prefecture; his resignation was reportedly an attempt to improve the DPJ's chances in the upcoming House of Councillors election in July 2010. Also incumbent party Secretary-General Ichirō Ozawa resigned on 4 June 2010 due to many recent scandals. Finance Minister Naoto Kan was widely expected to succeed Hatoyama, and a new government was expected to be formed on 7 June 2010.[1] On 3 June 2010 Shinji Tarutoko declared his candidacy to run against Naoto Kan for the leadership.[2] Apart from these two, Transport Minister Seiji Maehara and Foreign Affairs Minister Katsuya Okada were also seen as contenders, but both backed Kan.[3][4] Kan defeated Tarutoko by a vote of 291–129 with 2 invalid ballots was elected president of DPJ.[5]
Kan was seen as coming from the left of the DPJ and emphasized his independence from Ozawa; he succeeded in getting the backing of right-wingers Maehara, Okada and Yoshito Sengoku. He was sworn in as PM on the same day. A government reshuffle was expected over the weekend.[6]