Here's a link to Peter W. Galbraith's piece in the New York Review of Books, pointing out (as if it were necessary, but it is) that none of the benchmarks for the Iraqi government have been met or are likely to be met. Without a political solution no amount of military success can put Iraq back together.
Galbraith (Ken's son) and a long-time advocate for the Kurds, originally advocated a Shia-Sunni-Kurd partition of Iraq, but he seems to think it's too late for that now. "The Iraq war is lost." Bottom line? "...there are three missions that might be achievable -- disrupting al-Qaeda, preserving Kurdistan's democracy, and limiting Iran's increasing domination. These can all be served by a modest U.S. presence in Kurdistan."
Fred Kaplan, at Slate, respects Galbraith's argument, but thinks there might be some things we can still do in the rest of Iraq. It's a sign of how convinced he is that the lofty goals were never achievable that he limits his suggestion to aiding the Shia and Sunni to separate themselves from each other, helping with logistics and relocation aid and the like, before we leave the southern part of the country to its own devices.