Wondering why Ayatollah Sistani, the grand old man of the Iraqi Shia clerics and the man who, not long ago, was typically described as the most powerful man in Iraq, has been so quiet lately? He's under assault. All year long, partisans of Sistani's, including top aides, have been assassinated -- by whom, it isn't clear.

Today, two more Sistani aides were killed, one in Basra and another in Diwaniya. (That makes five since August.)

During that time, a war in Basra has broken out pitting Sadr, SIIC, and Fadhila forces and various gangs against each other. And two SIIC governors of southern provinces have been killed. Not to mention the armed clash that erupted in Karbala a couple of weeks ago, in which more than 50 Iraqis were killed. That clash pitted Sadr's forces against SIIC paramilitaries.

My own view is that Sadr's forces are a lot stronger than SIIC's. The army and police are bigger than either, of course, but who controls that, ultimately, is anybody's guess. If I were the United States, I'd bet on Sadr, and indeed there is talk of a U.S-Sadr dialogue underway. Then we read (in David Ignatius' column in the Post yesterday) that the United States has quietly given the green light to SIIC's Badr thugs to take control of Nasiriyah:

The American plan now, apparently, is to extend the Anbar model and create "bottom-up" solutions throughout Iraq. For example, I'm told that U.S. commanders met recently with the Shiite political organization known as the Supreme Islamic Iraqi Council and gave a green light for its Badr Organization militia to control security in Nasiriyah and some other areas in southern Iraq and thereby check the power of Moqtada al-Sadr's Mahdi Army. We're interposing ourselves here in an intra-Shiite battle we barely understand.