All week, school officials and community leaders in the Colorado town of Littleton have voiced utter incomprehension at why such a calamity should befall them. Columbine was one of the highest-achieving public schools in the Denver area, one of the main reasons why decent, respectable families chose to settle in Littleton, a God-fearing model community filled with large comfortable homes springing up with tremendous speed in the rolling green fields between Denver and the foothills of the Rocky Mountains. It is a near-ideal embodiment of the American Dream in the 1990s: an America that still yearns for open spaces and freedom while rooting itself in the comforts and conveniences of shopping malls and restaurant chains; an America increasingly wary of the melting-pot culture of big cities that seeks instead to create hermetic enclaves where decent folk can huddle with their own in safety.
Is this dream now turning to nightmare? After the classroom slaughters of Pearl, Mississippi, Jonesboro, Arkansas, West Paducah, Kentucky, Springfield, Oregon, and now Littleton - all of them fine upstanding middle-class communities - is anywhere safe for the nation's children?
Someone who might be able to provide an answer is Joe Costello. Costello is a 16-year-old punk with spikes in his hair and a large white skull printed on the back of his leather jacket who spent 18 months at a Littleton school very similar to Columbine, Chatfield High, before dropping out because he couldn't stand the hostility he drew.
"Just because I was different, just because I didn't believe in God or dress in Abercrombie & Fitch or play their dumb-ass sports, that gave the jocks an excuse to beat me up, to throw trash and rocks at me when I passed by, to call me a shithead and a fag," he said.
"Sometimes me and others like me who wanted to be different would get attacked in the administration offices but the authorities never did anything because the jocks are the kind of people they like and we are despised."
Costello seethed with much the same resentment as Harris and Klebold expressed to their friends and on their web pages. They, and their "Trenchcoat Mafia", were also teased and hit and accused of being gay at Columbine High. Talking to kids like Costello, it seems anger against the stifling conformism of suburbia is boiling away just below the surface.
"You can only take so much," he said. "I mean, these two were sick f- -ks, but you can see where they were coming from. If there's any good to come of this then maybe it's the message that jocks shouldn't pick on people who are different from them or else they might get blown away."
This was hardly a representative week in which to judge Littleton, but certain salient features jumped out. Like the smart houses, lines and lines of them scrubbed and identical, like Prozac pills laid out on a table. Or the sight of well-dressed teenagers driving Daddy's four-wheel drive and laughing at the nerdier, less affluent kids in their weather- beaten saloons.
Littleton has little public space to speak of, just a large mall whose security guards are forever hovering around the punks and the weirdos and threatening to throw them out. There are no cafes, no alternative bookstores, and just one slightly wacky clothing outlet called Hot Topic. A curfew keeps young people off the streets after 11pm during the week and midnight on weekends.
According to Costello and his friends, people put all their energy and their money into keeping up appearances - a nicely painted porch, a neat garden, the right upscale clothes, the appropriate appearance in church and at community events - and many less well-off residents are quietly ruining themselves in the process.
The determination to maintain appearances is compounded by the fact that community is defined by peer groups - a church, or a sports team - rather than more general neighbourly vigilance and goodwill. That might explain why Eric Harris could move from upstate New York three years ago as a bright student and keen sportsman, if slightly withdrawn, and gradually descend into destructive madness in a suburban cul-de-sac without anyone noticing.
When he and Klebold were put on probation last year for breaking into a van and stealing electrical equipment, they were obliged to attend an anger management course and - astonishingly - were deemed to have passed with flying colours. Their future, their case officer wrote just a few weeks ago, was full of promise and potential.
Littleton has been full of buzzwords this week - healing, community, closure - but the biggest reflex has been to go into denial rather than face such issues as the lack of functioning social or mental health services, the wide availability of guns and the dangers they pose, and the existential angst "different" teenagers clearly go through.
The first reactions to the shooting have only heightened the sense that difference is not tolerated - Denver schools banned trenchcoats, a Marilyn Manson concert scheduled for next week was cancelled, metal spikes on leather jackets have been outlawed, and so on.
The more searching questions have been raised by political and religious leaders in Denver, an altogether more liberal, diverse place. Mayor Wellington Webb, a black Democrat, told a public rally that parents and teachers had let children down and had to look where they had gone wrong. He also lobbied, with some success, for the National Rifle Association to stay out of Denver rather than hold their annual convention there this week. Law-makers in the state assembly also withdrew a trio of bills intended to loosen, rather than tighten, gun restrictions, delivering an unexpected victory to the liberals against deputies representing pro-gun communities exactly like Littleton up and down the state.
With every new school shooting, the NRA appears to go into retreat and gun control gets back on the agenda, both in Washington and in nominally conservative states such as Missouri and Florida. The big question is whether that retreat is temporary, or can lead to lasting reform.
In communities like Littleton, the prevailing belief is still that guns protect people more than they kill them. Perhaps the biggest test of the coming weeks is whether that attitude, and other deeply cherished notions of the suburban good life, are open to some radical re-examination and change.