Among the Shiites , the leading candidates for prime minister are thought to be Adil Abdul Mahdi , the Iraqi finance minister and a leader of the Supreme Council for the Islamic Revolution in Iraq ; Ibrhaim Jofferey , the head of the Dawa Party ; Hussein Shahristani , a nuclear scientist ; and Ahmad Chalabi , who marshaled support for the toppling of Saddam Hussein 's government in the Bush administration and has since become a pariah .