I don’t know what they call it these days in the military. It used to be called a "line of communication," (LOC) or a "Main Supply Route." These days it could be anything since the main line of intellectual advance in the services seems to be to invent new terms, abbreviations and acronyms for the simplest and most familiar things. "Front Line" is now called "Forward edge of the Battle Space." "How you do things," has become "Tactics, Techniques and Procedures" (TTP) This kind of fooling around is probably indicative of an absence of real thought.
An LOC is the road, railroad or combination of tracks overland that lead from your forward deployed forces to their supply base. George Marshall once put Patton into a main twist by inquiring politely "Where is your railhead, George?" This was in Champagne somewhere. There was no answer and Marshall got up and walked out of the room. Patton had a bad habit of ignoring things like railheads and as a result he often ran out of bullets, beans and gasoline. He could get a way with that because the German Army was in retreat and people like Marshall kept "fixing up" his railheads and roads behind him. If that had not occurred, then Patton’s 3rd Army would have ground to a halt with catastrophic results "for keeps" rather than just occasionally as a passing irritation to higher headquarters.
In Iraq, our LOC runs to the south through "Shialand" as someone described it to me recently. Down from the Baghdad area through Kut, Amara, Nasiriya and Basra to Kuwait where the roots of the supply base are. There is some resupply through Turkey, but the bulk of everything comes through and from the ports in Kuwait.
Airplanes? Hah! The tonnage just is not there, the tonnage and the bulk. It is helpful but not anything like enough to sustain the force in field. The British, etc.? I am glad they are there but anyone who thinks they could keep our LOC open if the Shia started working on closing the roads is smoking something "good."
Am I advising the Shia and their Iranian advisers on what to do? I do not think so. They are far too smart to have "missed" this vulnerability. It is there for all the world to see.
What should be done? As a matter of elementary prudence, we should position a large mobile force in Kuwait, so that we can re-open the roads north if need be.