If Iraq does slide into all-out civil war, the Bush Administration will have only itself to blame. It disregarded the advice of experts on Iraq, on nation-building, and on military operations. It staged both the invasion and the reconstruction on the cheap. It never learned from its mistakes and never committed adequate resources to accomplish either its original lofty aspirations or even its later, more modest goals. It refused to believe intelligence that contradicted its own views and doggedly insisted that reality conform to its wishes. In its breathtaking hubris, the Administration engineered a Greek tragedy in Iraq, the outcome of which may plague us for decades.
One of the interesting things to note is the suggestion that the disintegration of Iraq after the invasion for far from inevitable. Logically, therefore, there is a good reason to be supportive of the invasion decision, but opposed to the gross mismanagement that occured afterwards. While we wait for Baker et al, have a read of Pollack.