Muqtada al-Sadr is in the news, and it's not for renewed attacks by his Medhi Army. The Islamist has, instead, called for a peaceful demonstration against an Iraqi government agreement on the terms of U.S. military presence in Iraq, to take place following evening prayers.
Grand Ayatollah Ali al-Sistani, who didn't take sides when Hussein was being ousted by the United States, issued a slightly cryptic statement "forbid[ding] any stance that targets the sovereignty of Iraq no matter how small it is." It's unclear whether specific terms of the force reduction agreement offend al-Sistani as impugning the sovereignty of Iraq, although one lingering and offensive issue involving U.S. troops has been the power to try U.S. troops for activities within Iraq. Obvoiusly, United States officials cannot agree to turn American volunteer soldiers over to a nation with a recent history of protecting those who were engaged in murdering Americans for the crime of being American; however, Iraqi officials offended at the conduct of Blackwater contractors have a natural reason to demand meaningful accountability for the activities of armed foreigners roaming freely in their jurisdiction.
I assume that Americans won't be clearly subject to Iraqi civil and criminal authority under the terms of the agreement governing the draw-down and withdrawal of remaining U.S. troops, and that this alone is sufficient to offend al-Sistani. The presence of U.S. troops on any terms is, of course, a grave concern to al-Sadr, whose efforts to sieze power by naked force have been reeatedly thwarted by U.S. response.
The question remains whether al-Sadr will keep preaching nonviolent protest after Americans leave, or whether this is simply an ad campaign for future Islamist revolt against civil government. In the meantime, the plausible threat of force seems to be effective in dampening the overt threat posed by al-Sadr to the rule of law in Iraq. The fact that peaceful protest results in fewer deaths will hopefully not be lost on participants.
On the other hand, Fox News reports al-Sadr's actual position is that a new agreement on force deployment will be grounds to renew attacks. Maybe he hasn't learned his lesson, after all ....