After President Chen resigned as DPP chairman following the 2004 legislative elections, he was elected the 10th-term DPP chairman. Following DPP losses in the 2005 municipal elections on December 3, Su announced that he would, pursuant to a pre-election promise, resign from the chairmanship. Su is married to Chan Hsiu-ling (詹秀齡) with whom he has three daughters, one of which is Su Chiao-hui. Su was announced as the new premier on January 19, 2006 and took his oath of office, along with his cabinet, on January 25, 2006. Soon after, Su promised to step down if the people's welfare (referring to crime and other civil problems) did not improve within six months. Su faced calls for his resignation after the Rebar Chinese Bank run, but refused to leave his post at the time. Su was a contender for the DPP nomination in the 2008 presidential election. He formally announced his candidacy on Feb. 25. In the DPP primary vote on May 6, 2007, Su received 46,994 votes, coming in second to former Premier Frank Hsieh. Conceding defeat in the primary, Su announced that he had withdrawn from the race. On May 12, 2007, Su submitted his letter of resignation to President Chen Shui-bian, ending his tenure on May 21. With the resignation of Su and with ten months left in Chen's presidency, that would mean Chen's eight years as President will have seen at least six Premiers (with Chang Chun-Hsiung serving two separate tenures). Su also stated that he previously submitted resignations numerous times over his sixteen-month tenure, but all were rejected by President Chen. Su ran for Vice President alongside Frank Hsieh, who was the DPP Nomination. Together, Su and Hsieh ran against Ma and Siew. On March 22, they lost in a landslide to Ma and Siew's 7,659,014 (58.45%) votes with their 5,444,949 (41.55%) votes. Although Su had been considered a strong candidate to helm the newly created New Taipei City, because he had previously served the area as Taipei County Magistrate, he instead ran for the mayoralty of Taipei City. Su vowed that should he win, he would serve out the entire term (through 2014) effectively ending any talks of a presidential run in 2012. Su eventually lost the race to the incumbent mayor Hau Lung-pin.