"By the end of the Vietnam War, the American military had learned a good deal about how to fight a counterinsurgency war against a nationalist movement that used both conventional and guerrilla forces. The only problem was that few people wanted to remember either Vietnam or its lessons. There was, said T.X. Hammes, a Marine colonel who maintained an interest in counter-insurgency, “a pretty visceral reaction that we would not do this again.” American military training focused on conventional war; counter-insurgency was not even mentioned in the army’s core strategic planning in the 1970s. Hammes nevertheless studied the small wars in places such as Central America, Africa, and Afghanistan, and wrote a book on how to combat guerrilla warfare. A publisher turned it down: “Interesting book, well written, but a subject nobody’s interested in because it’s not going to happen.” The Sling and the Stone: On War in the 21st Century finally came out in 2004 as the Americans were painfully learning in Iraq the lessons they had chosen to forget. In 2005, General Petraeus, one of the few American generals to devise successful tactics in Iraq, set up a counter-insurgency academy there. Back in the United States, he made the study of counter-insurgency compulsory at the army’s advanced training colleges. Two books, T.E. Lawrence’s Seven Pillars of Wisdom, about the Arab revolt against the Turks during World War I, and Counterinsurgency Warfare by the French officer David Galula, became unexpected bestsellers in bookstores near army bases."