Good article summarizing recent fragmentation in the ruling Shia UIA coalition, as the Sadrists withdraw from the Cabinet and battle rages in Diwaniyah.

Monday's departure of six government cabinet ministers from the Iraqi government will indeed erode support for American-backed Prime Minister Nouri al-Maliki. The ministers represented radical cleric Moqtada al-Sadr, on whom Mr. Maliki relied to take the top government post in Iraq.

But the withdrawal of the Sadrists – who left in protest over the prime minister's refusal to set a date for the departure of US troops – highlights more troubling developments: widening fissures within the country's ruling coalition and a brewing Shiite fight for supremacy that threatens to unravel the leading political coalition, the United Iraqi Alliance (UIA).

...

The stakes are immense. The political battle is about control. Each Shiite party wants power in Baghdad, the so-called mid-Euphrates provinces, Najaf and Karbala, which are home to Shiite Islam's holiest sites, and the southern province Basra with its vital oil resources and maritime facilities.

"The only thing that [the parties] agree on is remaining in power and confronting one another. There is a negative meeting point, and that's not enough to build a government," says Mr. Dawod.

More than two years since their ascent to the helm for the first time in Iraq's modern history, Shiites have proven that the UIA is little more than a pragmatic marriage of convenience. So far, they have failed to transcend differences and reach out to the country's other communities, mainly the embattled Sunni Arabs.

"There is a great failure by the government," says Dawod. "And unfortunately, because of the situation in Iraq now, this failure does not lead to an alternative government coming to power but more chaos."

...

But beyond the political jostling, analysts say, the ultimate fate of the Maliki government may depend on the outcome of the fight for power unfolding on the ground. "There is a real war going on between Shiites in Basra, Diwaniyah, Karbala, and Najaf, and it's a mess," says Jabar.

He says Sadr's move Monday, as well as recent demonstrations, was simply a reaction to moves to dismantle his military capabilities, an effort being pursued cautiously by US forces, with the backing of Sadr's nemesis Hakim, who controls his own paramilitary group, the Badr Brigades.

In fact, several sources confirm now that a national police unit loyal to Badr was drafted from the city of Hilla into the deadly battles in Diwaniyah earlier this month between elements of Sadr's Mahdi Army and US and Iraqi forces.

Elsewhere, Shiite violence has erupted in even more unpredictable ways. The Interior Ministry said over the weekend that a bombing Saturday at a bus station in Karbala near sacred shrines that killed at least 50 people was the work of "renegade local elements and the Warriors of Heaven cult."

The government had accused fighters from the same cult of cooperating with Al Qaeda in January to unleash havoc in Najaf to fulfill a messianic vision. This prompted a fight between alleged members of this cult and US and Iraqi troops.

While the story of the cult may be plausible, Dawod says it may have been a theory promoted by the government to mask a bitter local fight.