I SPENT THE weekend watching my 4-year-old nephew. He went about the usual tasks that occupy little boys with his characteristic energy and bravado, crashing into walls, falling off chairs and running circles around his tired old aunt. He was a sturdy and indestructible trouper. And yet, I considered him as precious - and fragile - as a Faberge egg. I thanked God that he lived in Pennsylvania, not Newtown, Conn.

Of course as soon as I did that, I felt guilty for such gratitude when others were just beginning to grieve. But I would accept eternities of guilt rather than endure one minute of what the Newtown parents are experiencing.

There is nothing that matches, in the ferocity of its pain, the death of a child. Lose a spouse or lover, sibling or mother and you cry. But in those instances, what you are really grieving is the loss of your own relationship.

When a child dies, and particularly when the death is violent, the pain comes not only from the loss of your existing joy in their presence. What hurts even more than that - those things I recognized in my nephew like his laughter and boisterous but inquisitive ways - is the loss of potential. As a poet once wrote, the child is father to the man. In the clear gaze of a little boy, you have some idea of infinity; we don't know what he will become, but we have such glorious hopes for him.

When Adam Lanza murdered 20 innocent babies last week, he destroyed families and futures. He did it with bullets, his mind was unhinged, and we will now all talk about gun control and mental-health laws. These are discussions we should be having, should have been having all along, and those endless fights about the Second Amendment and the rights of the mentally diseased need to become more than just empty slogans.

Assault weapons should be banned; no private citizen needs to keep a military-style arsenal in his home, regardless of how people will tell you that bans are ineffective. The mentally suspect should not be roaming the streets simply because we don't want to infringe on their ACLU-fabricated right to pose a public danger. The homeless man who attacked me last month should have been in either a hospital bed or a jail cell, not loitering at Broad and Walnut.

Gun-control advocates need to sit down with NRA lobbyists and figure out how to guarantee that another massacre like the one in Newtown won't happen again, without depriving law-abiding citizens of the right to own a gun.

Mental-health workers, law-enforcement officials and civil-rights activists need to pool their resources and come up with a solution to help - or neutralize - the Adam Lanzas in our midst.

But this is not just a story of guns and insanity. It is not easily classified as a story about how the NRA has hijacked America or about how the mentally ill have been manipulated by the people who are supposedly fighting for their rights (while ignoring the rights of the general public). It is not the story of an assault-weapon ban foolishly allowed to expire, or of the ACLU opposing laws that would make it easier to commit the ill-but-violent.

This is about something sophisticated thinkers like to dismiss as superstition and idiocy, something we used to talk about with serious expressions and intentions and not smirk over at cocktail parties.

This is about the existence of evil.

Many are afraid to even mention the possibility, because it strips from us the ability to be "in control." If we admit that there is such a dark thing in this "enlightened" world, we are basically surrendering the capacity to map out our own destinies. Evil is that unplanned intruder that inserts itself unexpectedly into our daily lives and wreaks havoc. We don't like to think that people can actually be filled with evil, because it means we can't then medicate, or legislate, or educate it out of them.

Adam Lanza may not have been evil per se, but some part of him was invaded by those dark forces that poets and biblical scholars invoke. His demons, such as they were, could not have simply been a function of an addled mind. The ability to stare a child in the face with cold determination and then execute her is evil, and we would do well to acknowledge its presence in our society. No drug, no law and no amount of tolerance can fully eliminate it from our midst unless and until we regain an understanding of the preciousness of life. As long as we consider life to be disposable from its earliest presence in the womb to its manifestation in those who are no longer considered "useful" because of age or infirmity, we will continue to allow evil to flourish.

I cannot fathom the pain that this evil has caused to those poor Connecticut families. But I have found some comfort in these lines from a man who understood the evanescent beauty of childhood, Hans Christian Andersen:

Then the child opened its eyes, and looked into the angel's beautiful face, which beamed with happiness, and at the same moment they were in heaven, where joy and bliss reigned. The child received wings like the other angel, and they flew about together, hand in hand.

Blog: philly.com/flowers