This summer was a milestone for both me and my grandson when I was invited to speak at the baccalaureate service for his high school graduation. As I mingled with students and parents, I found that the only subject on their minds was—Littleton. Months after the tragedy, it is Littleton that seems to symbolize our fear for our children. I predict it will be remembered as a cultural watershed—the event that signaled the crackup of postmodernism.

As a philosophy, postmodernism draws inspiration from the writings of nineteenth-century philosopher Friedrich Nietzsche, who argued that "languages of good and evil" are rooted in neither truth nor reason, but in the will to power. Fifty years ago the Nazis fleshed out Nietzsche's ideas, resulting in horrific consequences; today two teenagers displaying Nazi symbols and slogans mowed down their classmates in cold blood.

Underlying the killers' fascination with swastikas and black uniforms was the outright embrace of evil—what literary critic Roger Shattuck calls an attitude of "approval towards moral and radical evil as evidence of superior human will and power." Denouncing the Christian ethic of love and obedience as "slave morality," Nietzsche called for a master race embracing brutality as evidence of its superior will and power. Who could imagine that two seemingly normal teens would take Nietzsche to heart?

Yet the wrenching irony is that they were only pushing to its logical conclusion the mindset of the surrounding adult culture. In the Atlantic Monthly, political scientist Francis Fukuyama says the decline in traditional morality in the West can be traced most directly to Nietzsche's view that moral principles are not objective; they are cultural inventions ...