I think it teaches us, above all, that we ourselves are the source of our social order. We are at choice as to what kind of world we live in. God has given us all free will. And what Americans have created for ourselves is a culture of violence. If the Columbine massacre forces us to face that, and if we do what it takes to turn this around, then those poor beautiful children will not have died in vain.
Love is the only effective counterveiling force to the fear-based energies of the modern world.
Until a critical mass of Americans commit to the creation of a culture of non-violence, then violence will continue to plague us. Some of us need to give up our guns. Some of us need to give up our violent videos and books. And some of us need to give up the unforgiveness that we harbor and have harbored in our hearts for years. As they say in recovery circles, if we keep acting the same way, there's no reason to expect different results.