Who is the rival cleric he is alleged to have done away with, why and how?
There are actually two ( at least ) clerical assassinations he may have had a hand in.
One was Abdul Majid al-Khoei, a son of the Grand Ayatollah who was probably the most revered Shi’a cleric of the late 20th century, eclipsing his student Khomeini, with who he had major doctrinal differences. The elder Khoei was the champion of the ‘quietist’ position that most Shi’a clergy ascribe to, as opposed to Khomeini’s idea of clerical rule. Sistani was another of Khoei’s students and his successor as the dominant cleric in Iraq and among the most revered in the Shi’a world generally. The younger Khoei was closely associated with Sistani and was seen by many of the Shi’a hotheads as being entirely too moderate and friendly with the U.S. ( the U.S. had personally flown him in after the invasion, and it appears the U.S. had in fact been backing him both politically and financially as a key moderate ). He was stabbed to death by a mob, that appears to have been instigated by al-Sadr.
The other is Mohammed Baqir al-Hakim, one of the leaders ( indeed the main one ) of SCIRI, the at one time Iran-based dissident movement, with ties to the Iranian clerical establishment. He was killed in a bomb attack which last I heard remains unsolved, but al-Sadr is on the short list of possible suspects ( might have been some other faction, however, like ex-Ba’athists looking to stir up the Shi’ites ).
Different Shi’a factions, but neither friendly to the upstart al-Sadr.
- Tamerlane
The rival cleric was Abdel-Majid al-Khoei. Al-Khoei was murdered in Najaf in April of 2003, probably by Sadr supporters: http://msnbc.msn.com/id/3068555/
Sadr denies any involvement, though it seems clear he resented al-Khoei.
He seems to be a very nasty preacher. Nonetheless, I won’t be turning in my Sadr-ing iron anytime soon. 