Former Taiwanese premier Su Tseng-chang's announcement that he plans to run in Taipei's mayoral election at the end of the year has been seen as a smart opening gambit for the 2012 presidential election. Analysts said that while Su had emerged as a big threat to the ruling Kuomintang in terms of both the mayoral and presidential polls, he had also left other heavyweights in the pro-independence Democratic Progressive Party pondering their next move. Ignoring a plan by DPP chairwoman Dr Tsai Ing-wen to field him as the party's mayoral candidate in the city of Xinbei - a special municipality formed by upgrading Taipei county - Su declared on Wednesday he would run for Taipei mayor. He said he had been Taipei county magistrate for two terms and felt it was time to run in the island's capital, a KMT stronghold. Su vowed in front of a Taipei temple that he would serve out his four-year term if elected mayor and stay clear of the 2012 presidential campaign. But he also said he was willing to 'make even greater contributions to the county to return its generous support', in a veiled reference to a possible presidential bid. Su's announcement would turn the Taipei mayoral poll into a showdown between the 62-year-old DPP politician and his KMT opponent, incumbent Mayor Hau Lung-bin, and threaten the KMT's grip on the capital, analysts said. Chen Chao-chien, an assistant professor of public affairs at Ming Chuan University, said even though support for the KMT in Taipei regularly hit more than 60 per cent, 'there is a chance Su might win'. Voters' disappointment in Taiwanese President Ma Ying-jeou's government and some defective construction projects in the city - including a new section of subway and a suburban cable-car system, both started by Ma when he was mayor - had eroded Hau's popularity since his election in 2006, Chen said. The bid by Su, a highly efficient and practical politician whose two terms as Taipei county magistrate between 1997 and 2003 won praise from residents, poses a big challenge to Hau, although he insists he is confident of being re-elected for another four-year term. Analysts said Hau was likely to win, in a close fight, but that the campaign would provide Su with a much-needed political stage to justify a presidential bid in the face of competition from other DPP heavyweights, including the party chairwoman, who has strengthened her position by helping the DPP win a series of elections since December. 'Defeated in the mayoral race or not, Su would still be the biggest winner,' Chen said. While Su was seeking to follow in the footsteps of former president Chen Shui-bian, who won the presidency in 2000 after failing to be elected Taipei mayor, he was also earning political capital he could use to challenge Tsai. She has helped the party get back on its feet after humiliating poll defeats blamed on the graft-tainted Chen Shui-bian, who was denounced by voters after he was charged with corruption over his activities while president, Chen said. Analysts said Su's bid had totally disrupted Tsai's nomination plans, because she had hoped to keep Su in Xinbei to secure the DPP's victory in the majority of the five special municipality elections. If Su was elected in Xinbei it would give the DPP three municipalities, as it had full control of Kaohsiung and Tainan in the south, said George Tsai Wei, political science professor at Chinese Taipei University in Taipei. 'This would consolidate Tsai's unchallenged party leadership status and increase her chance in the 2012 presidential bid,' he said, adding Su's latest move had put a damper on Tsai's presidential prospects. Taichung - the other special municipality, in central Taiwan - is seen as unconquerable for the DPP, given the high level of support for incumbent Mayor Jason Hu Chih-chang of the KMT.