First, "status quo ante" is a clear victory for Sadr, given that Maliki set the bar for himself as total victory.
Second, he's probably right that it isn't just status quo ante - numerous sources today report that Maliki has issued an order ending the extralegal raids and arrests which had been a primary complaint of Sadrists for months, which suggests that the new status quo does include at least one significant gain for the Sadrists.
as I argued yesterday, everything still depends on what happens next. Sadrists are talking about bringing a no-confidence vote against Maliki and complaining of ongoing
harrassment, some of Maliki's advisers are talking about continuing
military activities in Basra, various political groupings are speaking out in support of and in opposition to the government's actions... in other words, I'll stick to my point
that it's going to be a while before the real political winners become clear, whatever the military outcome. In a rapidly shifting environment, it's risky to declare victory before you see how things shake out. Keep an eye on the political war and the implementation phase.
In that regard, I do want to flag the most optimistic possibility, raised in this fine Christian Science Monitor op-ed that something positive in terms of building Iraqi state capacity could still come of this. If the government and the US can work with the Sadrists to build political consensus around the establishment of state sovereignty over Basra, it would be a major positive step. It doesn't seem likely in the current political atmosphere, but it's where I would like to see efforts directed right now. In that regard, it's interesting to have another look at Sadr's interview with al-Jazeera's Ghassan bin Jiddu... which I'll write a bit more about when I get a few minutes.