No sooner had we learned of the school shootings in suburban San Diego, Calif., in which two youngsters died and 13 more people were wounded, than yet another student was wounded by a classmate in Pennsylvania.

Soon after, within 100 miles of Monday’s carnage in California, police uncovered a bomb plot at a middle school, as well as a group of students at another school with guns and a list of people they reportedly planned to use them on.

A collective groan goes up across the country and we shake our heads in disbelief, just as we have so many times before through nearly an entire decade of this utterly senseless and incomprehensible violence committed by children against children.

And once again, we comb the now-familiar grounds in a desperate search for answers that have eluded us ever since we were introduced, through images filled with bloodshed and grief, to places such as Paducah, Pearl, Springfield, Jonesboro and Littleton.

We trot out the usual suspects – those potentially corruptive social influences that our frenzied culture seems to manufacture daily – in the hope that maybe this time they can supply the missing clues to the tragic puzzle that confronts us as a nation. We pry into the damaged psyches of these baby-faced criminals and, as usual, we come up empty.

The school administrators can’t find the answers. Neither can the teachers, the classmates, the friends, the clergy, or the politicians. Neither can the parents, who have no choice anymore but to worry whether sudden violence will one day touch their own children, as it has so many others in towns no different from their own.

While we know how a nation teeming with handguns can make it so easy for these troubled kids to kill, we still have no clear idea what makes them take up arms in the first place.

At this point, perhaps the greatest risk we face is that we might eventually stop looking for the answers we need, that we might resign ourselves to the numbing sameness of it all and concede that youth violence is simply an unavoidable element of modern life. Just put up metal detectors at the entrances to our schools, monitor the halls with guards and surveillance cameras, pat down the kids as they arrive in the morning and pray that nothing bad comes their way.

After all, how many more of these tragic stories can we possibly absorb before we lose our capacity to be shocked by events that once were unthinkable but now seem almost routine? Perhaps some of us have lost that capacity already. If so, can we ever really hope to find the solution that might restore to our children’s lives the sense of security and well-being they deserve?

Somewhere there must be an answer to why young people, for the first time in our history, feel compelled to arm themselves like soldiers and wantonly destroy the lives of the very kids and teachers they see each day at school. Finding that elusive answer is more than just a challenge for the experts; it is also the gravest responsibility that any parent can undertake in guiding a child safely through a world full of hazards.

As parents, are we fully prepared to say that we have done all the hard work necessary, put in all the time and attention that’s required, to understand all we can about what is going on in our children’s hearts and minds? If we can learn anything from the long list of past tragedies – and the ones that are almost certain to come – perhaps it is that none of us can afford to forsake the critical obligations that come with the most important job in the world.

It’s not the only answer to the problem of youth violence, of course, but it’s the only one we’ve got.