Mr. Tan's candidacy would intensify what is shaping up to be the most keenly contested presidential vote since the introduction of the elected presidency in 1991. The post has no executive authority and isn't involved in day-to-day running of the government. It does carry certain veto powers to safeguard Singapore's reserves, and some responsibility over civil-service appointments and government and statutory board budgets.
Mr. Tan will also resign as chairman of the media group Singapore Press Holdings Ltd. as of July 1.
