Not so long ago, the Indy's Patrick Cockburn suggested that the Sunni insurgents - the New-Old Iraqi Army, as I call them - are pursuing a strategy of encirclement as a counter to the Shia majority in Baghdad, pressing hard around Baqubah and Muqdadiyah to the north and the Mahmoudiyah/Iskandariyah area to the south in order to control the road and rail exits from the city. There has been a great deal of fighting in these places, and the Baqubah area has been very bad recently. It's in Diyala province, which is a near-even mix religiously, and commands the last major road out of Shia Baghdad. Cockburn's sources described a typical process - a big bang, then the intimidation of the police, then the elimination of local businesses so as to force everyone else out. Then, Sunni refugees from Baghdad appear in a convoy and move in. No doubt they will be asked to find a self-defence force, as was done in 1940 in the Warthegau of German-occupied Poland.
The NYT reports on the counterstrategy, which is to do the same to the Sunnis on the remaining road out in the hope of incorporating that territory in the future Shia state. The ethnic cleansing is indeed under way. It's a horrible old European story - kill one lot, move them out, find enough of yours to secure the ground.
Here is a useful suggestion, now that the field is apparently open to useful suggestions - in the interval between now and withdrawal, the Coalition and the Iraqi government should declare the neutralisation of the roads north and south out of Baghdad, and bomb the hell out of anyone who interferes. If you want a humanitarian intervention, permitting the citizenry to escape Baghdad is it, as is staving off either an assault by the NOIA or a breakout by the SCIRI a while longer.
Update, 1231GMT 16/11/06: The Saudis are shitting bricks, as are the Syrians, the Turks and the GCC. But can we not take up Nawaf Obeid of CSIS on his suggestion, though? The last thing we need is Saudi Arabia warning Iran that, unless it stops it's messing around, the Saudis will start their own proxy-war effort in Iraq. To be filed under "fighting fires with petrol".