Iran’s supreme leader’s second son, Mojtaba Khamenei, has emerged as one of the driving forces behind the government’s crackdown, diplomats and observers said . Mojtaba is an ally of Mahmoud Ahmadinejad, the disputed president, and was credited with winning his father’s endorsement for the then Tehran mayor in the 2005 elections, leading to Ahmadinejad’s shock second round victory. Mojtaba is an austere figure, generally seen as more hardline than his father and has become a gatekeeper for access to the beit-e-rahbari, the supreme leader’s home, and the supreme leader himself. According to some Iran analysts, Khamenei, 70, is manoeuvring to position his son as his successor. Formally, the position is supposed to be awarded by the assembly of experts, an elected group of clerics led by the most powerful rival to Khamenei and Ahmadinejad, Hashemi Rafsanjani. But the first supreme leader, Ruhollah Khomeini, had a powerful say on who his successor should be.