Yukio Hatoyama and the DPJ came into power after their historic victory in the 2009 general election. The DPJ won more than 300 House of Representatives seats in the election and inflicted the worst defeat for a sitting government in modern Japanese history to the LDP. Hatoyama entered office with high approval ratings amid high public expectations to recover the Great Recession-hit economy and reform Japan's stagnant politics. These high expectations contributed to a drop in popularity of the government. The government became more unpopular after it broke a campaign promise of closing down an American air base in Okinawa. Hatoyama initially moved to close down the base after the election, but relented to the pressure from the American government. Hatoyama also cited the escalation of tension in the Korean Peninsula following the sinking of South Korean Navy corvette "Cheonan" as a factor that contributed to the base being kept. The continuous drop in the government's approval ratings led to Hatoyama's resignation on 2 June 2010.