Basra will be the test of Maliki
The logic of this is pretty reasonable, theoretically allowing Maliki to build some credibility by cracking down on other Shia before the Shia led government begins operations against Sunnis. But the big question/gamble in this is, will the Shia coalition survive these security operations?
There was a pretty interesting article over the weekend about the source of the current Basra flare up. One of the main agitants in the area is the Shia Fadhila party which holds the governorship. This group has pulled out of Maliki's government coalition and has issued a "go slow" on oil production/exports.
That's the other reason this battle is the one being chosen by Maliki. Almost all revenue on which the Iraqi government runs passes through the pipelines and export terminals of the region. In effect, it is a dispute over how much of the revenue will go to the official government, Maliki's coalition, and the local Shia militias.
So, keep an eye on Basra over the next month. If Maliki fails there, or it leads to a cracking of his coalition, it could have serious ramifications.
And, just as a complicating factor, the British military, who have been tasked with managing Basra for the last three years, are now saying that the upsurge there is being spearheaded by "foreign terrorists, led by fighters from Saudi Arabia." Also, it's not very clear where Iran might fall in all of this. They're very active in the area.
UPDATE: The NYTimes has a pretty good piece describing some of the elements of the Basra violence.