The dramatic decline in bloodshed in Iraq – at least until last week’s terrible market bombings in Baghdad – is largely due to Muqtada al-Sadr’s August 2007 unilateral ceasefire. Made under heavy U.S. and Iraqi pressure and as a result of growing discontent from his own Shiite base, Muqtada’s decision to curb his unruly movement was a positive step. But the situation remains highly fragile and potentially reversible. If the U.S. and others seek to press their advantage and deal the Sadrists a mortal blow, these gains are likely to be squandered, with Iraq experiencing yet another explosion of violence. The need is instead to work at converting Muqtada’s unilateral measure into a more comprehensive multilateral ceasefire that can create conditions for the movement to evolve into a fully legitimate political actor.