Sporting a three-quarter-length parka, the 14-year-old boy sauntered toward the doors of W.R. Myers High School in Taber, a small town in the Canadian province of Alberta. Someone smirked, "Do you have a gun under there?" He did. Moments later, the ninth-grade dropout whipped out a .22-cal. rifle, killing a 17-year-old boy and critically wounding another.
On its own, the crime would have been horrible enough. But coming just eight days after the Littleton massacre, it was the centerpiece of a fevered week of copycat incidents at schools across the continent. Authorities rounded up scores of kids for allegedly plotting...