Many people, even alleged conservatives, blame the West when it comes to explaining Islamic terrorism. If it wasn’t the crusades, it was the end of World War One, when Winston Churchill and T. E. Lawrence (of Arabia), among others, carved up the map of the modern Middle East.

But if the collapse of the Ottoman Empire and the creation of modern Iraq, Syria, Jordan, and Palestine (eventually Israel) were a cause of movements like ISIS, why was the region relatively quiescent after the First World War? Indeed, Lawrence, in 1922, predicted that even among the ever restless Arabs, there would “be no more serious trouble for at least seven years,” which, in those territories for which Britain was responsible, proved broadly true. In 1935, he wrote to Robert Graves, “How well the Middle East has done: it, more than any other part of the world, has gained from the war.”

Lawrence thought that West had little to fear from Arab nationalism, because the Arabs were “even less stable than the Turks” and if “properly handled [the Arabs] would remain in a state of political mosaic, a tissue of small jealous principalities incapable of cohesion and yet always ready to combine against an outside force.”

The British were used to putting down jihadists, whether in the Sudan, or in India, or even 1920s Iraq, and did so with an eye on frugality. Crushing jihadists, it was thought (and proved), needn’t be expensive. When Lawrence noted a  “Wahhabi-like Moslem form of Bolshevism” welling up in Southern Iraq, it was the RAF that dispelled it, using on-the-ground spotters like John Bagot Glubb, whose Southern Desert Camel Corps, made up of Iraqi border Arabs, later patrolled the border to keep the Wahhabist Ikhwan out...