But what is still more terrifying is that following the school deaths in Oregon, just as after the shootings in Jonesboro, Arkansas and all the others, the warnings and the demands for action will go unheard. "We have a very serious problem. It's an epidemic of gun violence in America's schools and we have to do the responsible thing," says Bob Walker, of Handgun Control Inc, a lobby group that is fighting to limit the ownership of small arms. "Every American has a responsibility to keep guns out of the hands of children," he told CNN on Thursday night.
Yet when the President made a speech yesterday, what was the great threat he identified? Biological weapons. The US is to increase its stocks of antidotes to anthrax and so on; the menace of guns will continue.
Everyone knows a Kip Kinkel at school - weird, maladjusted, a bit dangerous. He was voted the child "most likely to start World War III" by his classmates. One said that "he would, like, torture animals and stuff, and tell us about it." But in Britain, the worst those kids can do is small beer indeed. They can't get hold of a semi-automatic rifle and spray their classmates with bullets.
In the US, the Constitution - written 200 years ago, when America was a frontier society, when guns meant single-shot muzzle loaders - protects the right to bear arms. And a significant part of American mythology is based around that right, the need to get mad and to get even through the great equaliser.
When a poll for CNN asked Americans who they blamed for tragedies like that in Oregon,28 per cent blamed the parents. Mr and Mrs Kinkel, it seems, were the first casualties of their son's black, irrepressible fury early on Thursday morning in the district they called Shangri La. Then he put on his coat and headed out with a rifle under his arm and a pistol in his holster, with the US Constitution right behind him.