THE resignation of ageing Taiwanese premier Mr Hau Pei-tsun provides President Lee Teng-hui with an opportunity to rejuvenate the party leadership. Yet Mr Hau's vociferous popular support suggests the wrong choice of successor could backfire badly. A four-star general, Mr Hau's main backing came from the right wing of the ruling Kuomintang (KMT) and the army. However, he earned the respect of the business community, and polls show the public also regarded the ousted premier as a force for stability. He was seen as a better choice to deal with Beijing than any candidate from the President's faction. Many individual members of Mr Hau's ''non-mainstream'' faction favour more direct links with the mainland. Mr Lee wants to give his government a younger image. Unlike the conservative faction's elderly candidate Mr Lin Yang-kang, the mainstream's Mr Lien Chan would fit that bill. However he must also show he stands for change. In December's elections, mainstream candidates did poorly because they were associated with ''money politics'' and ''politics as usual''. Mr Lee is perceived as dictatorial and increasingly concerned about his own political fortunes. Mr Lien is widely perceived as too much the President's man. Whoever he picks must show he favours clean, incorruptible government and is committed to policies that will neither compromise Taiwan's status nor infuriate Beijing by stressing the island's separate identity.