Ex-prime minister Najib Abdul Razak's high profile campaign in the Johor polls has sparked a debate about whether a man convicted of criminal breach of trust, money laundering and abuse of power will be a boon or bane for BN.

Najib's allies, such as Johor Umno chief Nur Jazlan Mohamed, has been unabashed about pushing the leader accused of corruption but the ex-prime minister's cousin Hishammuddin...