Read the whole thing, which goes on to eviscerate all the excuses the neocons now make.
The strategy failed because of one big, bad idea at its very root. [Namely, the neocons'] idea that we kick the door in. Everything has flowed from that.
We were not invited. We had no mandate. There were no "good" Iraqis to hand over to. We had nothing to latch on to, no legitimacy. It wasn't a question of being tactful, respectful, munificent, or handing sweets to children. We were impostors, and that is all.
Some wars you're just going to lose, regardless of the brilliance of your strategy. Postcolonial wars of occupation, without an exception I can think of, all fall into that category.