At the heart of the Minnesota shooting tragedy was a profoundly troubled and isolated teenager. There are unlikely to be any simple answers to the question of why events unfolded as they did this week and how the shooting could have been prevented. But there are signs that Jeffrey Weise's problems were repeatedly overlooked and perhaps even dismissed.
The loss of 10 lives, including the teenager's own, was also made possible by what are the loosest gun control laws in the developed world.
After this shooting, there will be calls for tighter security at schools. But more metal detectors and even guards - Weise's school had both, as do many other schools - are not the answer alone. A broader approach is needed, including better social and psychological counselling for students, conflict-resolution workshops and, most importantly, better knowledge of the problems teenagers are confronting.
Every time an incident like this makes the headlines, the world is able to see that for all the material wealth the United States can claim, some of its children face daunting emotional problems.
The antisocial rage that drove Weise may not be uniquely American: school shootings and Columbine-inspired plans have been witnessed or foiled from Canada to Japan. But the distressing regularity of such news from all parts of the United States should lead to soul-searching.
There were elements of Weise's life that should have triggered alarm. They included his father's suicide, his mother's confinement to a hospital after suffering brain damage in a car accident, a flirtation with neo-Nazi ideology and alienation from those around him.
Writing under pseudonyms in internet chat rooms, he claimed to have been investigated last year for a threat to 'shoot up' his school. More recently, he showed graphically violent drawings around and was suspended from school for an unspecified reason.