Going after Mahdi Army?

Thanks to Juan Cole for the tip off. The Arabic Dal Al-Hayat is reporting (translation) that

there are some secret paragraphs to the agreement between the Bush administration and the al-Maliki government in Iraq to act against militia leaders. The article suggests that the model of the US raid on an Iranian liason office in Irbil might be deployed against Mahdi Army leaders and against Sunni Arab guerrilla commanders. That is, such raids would be small, targeted, quick and involve kidnapping suspected wrongdoers.

"The article also quotes US ambassador in Baghdad, Zalmay Khalilzad, as saying that al-Maliki promised Bush that he would confront the [Shiite] Mahdi Army.

That might sound good, but I fear it is exactly this sort of strategy that could fragment the Mahdi Army at a time where the US benefits greatly from it being together. I feel this is the sort of thing that leads to a worst case scenario (as posted early) come into play.