I really meant to attend this GW event with Stephen Biddle, Nora Bensahel, and Larry Corb on Friday but I wound up unable to make it. Marc Lynch was there and recounts Biddle's argument that the surge might work: "if everything goes right and if the US continues to 'hit the lottery' with the spread of local ceasefires and none of a dozen different spoilers happens, then a patchwork of local ceasefires between heavily armed, mistrustful communities could possibly hold if and only if the US keeps 80,000-100,000 troops in Iraq for the next twenty to thirty years."

I guess I agree with that. To me, it sounds like a very good reason to leave. I'm not sure where Biddle stands on that, since he's usually tended to stay a bit cagey as to what policy recommendations he would make. At any it seems clear to me that even the "optimistic" scenarios for Iraq now amount to promising to bear huge costs for a smallish chance at an unclear payoff.