Civil wars can be especially atrocious as neighbors kill each other at close range, but they also have a purpose. They can bring lasting peace by destroying the will to fight and by removing the motives and opportunities for further violence.
The logic is very sound. Of course, the White House will have a hard time accepting this rationale -- it will be a bitter pill for the Republicans to swallow if they acknowledge that they have to step aside and let the country implode so that the Iraqi people can eventually move forward.