As per NY times,
http://www.nytimes.com/2006/07/26/world/middleeast/26military.html?ref=world&pagewanted=printthe US is going to pull troops from other areas into Baghdad, where it will secure neighborhood after neighborhood in an "ink-blot" fashion, until all of Baghdad is secure. Let me predict what will happen:
1) the US will lose control, tenuous as it is, of peripheral provinces, where ethnic cleansing and murder will proceed unabated.
2) If they don't get Al Sadr on board beforehand, Al Sadr's militia will resist American-lead units. Baghdad becomes Fallujah, with street fighting for every block. Baghdad will be turned into rubble with a massive humanitarian crisis to follow.
3) Al Maliki's government will fall apart, Baghdad will be ruled by militias a la Mogadiscio.
4) Americans evacuate Baghdad, Iraqis who work in the green zone are airlifted a la Saigon.
5) US leaves Iraq