In 2006, the military wrote a new counterinsurgency field manual, and Nagl was a lead author. The central lessons of the manual, as Nagl put it in a piece he co-wrote in Foreign Policy magazine in February, are "simple, but radical: Focus on protecting civilians over killing the enemy. Assume greater risk. Use minimum, not maximum, force."
Others were even more expansive in their vision of the future of war. Lt. Gen. William B. Caldwell, who guides the development of Army doctrine as the commander of the Combined Arms Center at Fort Leavenworth, Kan., put it this way in an article he co-wrote in Military Review last summer.
"The future is not one of major battles and engagements fought by armies on battlefields devoid of population; instead, the course of conflict will be decided by forces operating among the people of the world," he wrote. "Here, the margin of victory will be measured in far different terms than the wars of our past. The allegiance, trust, and confidence of populations will be the final arbiters of success."
That shift in focus may rankle some officers, but it is hardly radical today. On Aug. 26, McChrystal, head of the International Security Assistance Force (ISAF), the NATO command for US and allied efforts in Afghanistan, issued a six-page memo on counterinsurgency guidance that showed how much he's committed to the new way of war. Its first two sentences: "ISAF's mission is to help the Islamic Republic of Afghanistan defeat the insurgency threatening their country. Protecting the Afghan people is the mission."