From Columbine (which happened on April 20, 1999) until Virginia Tech (which happened almost exactly 8 years later, on April 17, 2007), virtually every school shooting has been carried out by alienated, abused boys filled with rage and anger at a world which they see as having rejected them. Yet 40 states still lack comprehensive anti-bullying laws and little has been done to address bullying, which the Harris polling organization found in the 2005 report From Teasing to Torment: School Climate in America has been experienced by 65% of all high school students. As an old coach of mine once said, "You keep doing what you're doing, you'll keep getting what you've been getting."
Obviously young men like Eric Harris, Dylan Klebold, and Cho Seung-Hui who perpetrate tragedies like Columbine and Virginia Tech are deeply troubled individuals. Most students who get bullied don't go berserk and gun down their classmates. Usually they simply drift away from school, eventually dropping out, or turn their anger and rage inward, where it manifests as depression, eating disorders, substance abuse, and suicidal behaviors. By hurting only themselves, they allow us to ignore the problem - at least until the next spasm of murderous rage like the one we saw at Virginia Tech this week.