Former Umno president Datuk Seri Najib Razak on Tuesday said it was up to the party leadership to decide on whether his successor, Datuk Seri Dr Ahmad Zahid Hamidi should go on leave amid his corruption charges. Last Sunday, Umno veteran Tengku Razaleigh Hamzah said the party constitution is silent on the matter but there has been precedence with former Youth chief Datuk Seri Harun Idris and former Umno vice-president Tan Sri Muhammad Muhammad Taib giving up their positions in such cases.