New troops will be in Iraq not to police the streets and hold the line against the creeping violence, but to expand the war by taking on the Shia militias. This is an escalation strategy. Will it work; maybe, maybe not. But it runs the risk that it may very well provoke a Shia insurgency—something Iraq has not so far witnessed. Thus far the U.S. has faced a Sunni insurgency (which by most estimates continues to account for 80% of U.S. casualties), and sectarian violence in which Shias and Sunnis are killing each other. Shia militias are violent, destructive and radical, but Shia militias are a very different problem from the Sunni insurgency. Shia militias, unlike te insurgency, are not targeting American troops. But it looks like the administration is set to change that. Over the past year Washington and its Baghdad embassy have alienated the Shia and undermined the authority of the more moderate Ayatollah Sistani. Anti-Americanism has grown in Shia ranks as they accuse U.S. of favoring Sunnis by focusing on Shia militias rather than Sunni insurgency. By going to war with the increasingly popular Sadr Washington runs the danger of losing the Shia altogether.
If he's right, it would be unsurprising if the Joint Chiefs are worried. On the other hand, it might succeed in unifying the Iraqis - against us.