It was August 2004, and the Iraqi insurgency was raging in Anbar province. Major General James “Mad Dog” Mattis of the Marines, who is now the Trump administration’s defense secretary, called a meeting with a group of religious leaders outside Fallujah. His division was coming under daily fire from both local militants and foreign terrorists associated with al-Qaeda’s affiliate in Iraq, and he hoped to persuade the leaders that it was misguided of them to encourage local young men to pick up rifles and shoot at American forces rather than trying to throw out al-Qaeda, whose bombings and beheadings were transforming their province into a hellscape.