From Vanity Fair:
He still steers the Iraq war, and he oversees the developing strategy for routing the Taliban in Afghanistan. The all-out assault on Marjah in February demonstrated strict Petraean principles in action. It was announced months in advance, which gave civilians a chance to either dig in or clear out. There were civilian deaths, tragedies that were clearly inadvertent and which McChrystal publicly apologized for, but the numbers were a fraction of those common in such urban assaults. By so carefully reducing the potential for civilians to be caught in the crossfire, the offensive all but eliminated what is, perhaps, the strongest incentive for Taliban troops to stand and fight: to exploit such deaths to turn public opinion against America. Since they could not hope to defeat the onslaught of allied and Afghan troops, the insurgents largely melted away. The end result was the same: the allied and Afghan forces reclaimed Marjah, but they did so with relatively little bloodshed. This approach runs directly counter to military convention, which prizes secrecy and surprise. It recognizes that the real battle is not chasing the Taliban out of the city or underground but winning the population, a process which can begin only after the city has been retaken. American commanders have already announced an even larger offensive for later this year, on Kandahar.
Ducks and Economics 