“May Allah accept this from me.”“I’m doing it in the name of Allah.”“To establish Islamic law—Allah’s law on earth.”The above are statements made by would-be and successful jihadists to explain their motivations for planning or executing acts of terror in America. Jihadists in other parts of the world say much the same thing. Where, then, do they get the idea that this is what Allah wants them to do?Jihadists usually cite the Koran as the source of their motivation. For example, Terry Lee Loewen explained his planned jihad attack on Wichita’s Mid-Continent Airport last December as follows:I don’t understand...