The NYT reported last year:
"As British troops pull out of their last base in Basra, some military commanders and civilian government officials in the area are concerned that the transition could leave them and a major supply route to Baghdad at greater risk of attack. The route, a lifeline that carries fuel, food, ammunition and equipment for the war, crosses desert territory that is home to rival militias and criminal gangs. In interviews, Americans stationed in the southern provinces and Pentagon planners say they are closely watching the situation there as the British pass security responsibility to local Iraqi units.
There is little talk of increasing the American troop presence along the major supply route, which links Baghdad and Kuwait and is called M.S.R. Tampa, although officials in Baghdad and Washington say other options include increased patrols by armed surveillance aircraft, attack helicopters and combat jets."
http://www.globalpolicy.org/security/issues/iraq/occupation/2007/0915supplylines.htmNote, the lack of any use of boots on the ground in that plan. If the Brains Trust at HQ Patraeus think they'll be able to protect their main line of communication with helicopters and jets flying at 14,000 they're seriously in dreamland. If Sadr really wanted to mess things up majorley, he'd go after our supply convoys in a big way. That would present Patraeus with the choice of using troops to back al-Maliki's military folly in Baghdad or rush them south. Of course, he does that and he has to give up on pacifying Baghdad and possibly leaving the Green Zone even more vulnerable.