What degree of punishment – ta’azeer or hadd – should be imposed on one, who claims to be a practising Muslim, yet does not believe that Imam Ali (A.S) is superior to any prophet other than Muhammad (PBUH)?

Such a person should be introduced to, and have explained to them, the ‘roots’ of the faith – Usul al-Din – which collectively form the basis of Islamic belief – aqidah. The Imamah is a part of belief and nothing to do with the practice of Islam.