There was the predictable cry for gun control from some politicians. Most Americans no longer buy this; they know gun control isn't the solution, but many citizens haven't a clue what is. And we'll continue to be both perplexed and fearful until we face an uncomfortable fact: We share the blame for schoolyard slaughters by allowing our kids to form a parallel culture almost completely free of adult supervision.

Leon Botstein, president of Baird College, characterizes American schools as "a gang in which individuals of the same age group define each other's world." Within this alternate universe, kids are free to determine not only hair and clothing styles, but also moral fashions: They decide the rules governing sexual behavior and drug and alcohol use. And if those rules sometimes produce bloodshed as at Santana—well, we shouldn't be surprised. The classic novel Lord of the Flies warns what happens when children go without adult guidance: They quickly descend into savagery. At least the children in William Golding's novel didn't have adults encouraging them, as real-life kids do. For, ironically, it is business-suited adults who support the parallel teen culture.

For contemporary teens, the highest value is simply being "cool." How do kids define cool? It's an amalgam of ideas fed to them by corporations that covet the $150 billion-a-year teen market. As the PBS documentary The Merchants of Cool reports, these are the clothing manufacturers, media empires and soft-drink companies that make it their business to know what teenagers want.

And what do they want? First, an adult-free universe—which ...