Without that lie about American aggression, none of the many verses of the Qur’an that bin Laden cites would justify violence, much less the unholy slaughter of civilians. There are many interpretations of jihad–which means, literally, “effort.” Often it describes the personal struggle merely to be a better, more pious Muslim. The empire builders of Islam waged military offensives in the name of jihad as late as the 17th century, and not a few turned their righteous doctrines on each other. But according to Gilles Kepel, author of the forthcoming book “Jihad: The Trail of Political Islam,” the defensive holy war that bin Laden claims to fight is the most potent and most dangerous form of all. It is seen by many Muslims, if it is justified, as a personal obligation that supersedes all others, and may ultimately challenge all authority. “It’s a two-edged sword,” says Kepel. “Once you open the gate of defensive jihad, it’s very difficult to close it again.”

“To those against whom war is made, permission is given to fight,” says the 22d chapter of the Qur’an–especially “those who have been expelled from their homes… for no cause except that they say, ‘Our Lord is Allah’.” Thus in Muslim theology defensive holy war was justified against European Crusaders and conquerors who attacked Muslims in the name of Christ and imposed the Inquisition, with all its horrors. Thus, in more recent times, Afghans could wage their war against the atheistic Soviets with plenty of religious backing. Few if any Muslim scholars will speak out against jihad by Palestinians fighting Israeli occupying troops. But bin Laden, a Saudi, was never persecuted for his faith. The goals he fought for initially were political and personal: to overthrow the Muslim rulers of his own country. And the jihad he declared against the United States, in the eyes of most religious scholars, was never a holy war, it was a blatant fraud.