Within the past 20 years, in my hometown of Montreal (Quebec), there have been three sets of shootings of college students. One took place at the Ecole Polytechnique in 1989 (affiliated with the University of Montreal), another (smaller) at Concordia University, and one recently at Dawson College. In the first attack 14 women died, in the last the toll was limited only by courage, good fortune and rapid medical care.
The Polytechnique massacre led to stricter gun control laws in Canada. I believe the weapon used in the Dawson shooting was illegal in Canada, but it is widely sold in the US.
In the US there is Columbine and now Blacksburg.
Has anything changed? If we look back at the last fifty years in North America, and we adjust for population growth, will we see intermittent episodes of these events?
I suspect modern hand held weaponry is lighter and smaller, easier to acquire (even where it is not legal), easier to operate, more affordable and more lethal than the weapons of twenty years ago. Is technology change alone responsible for any increased lethality of school shootings? Or perhaps there's no clear pattern at all.
I can't imagine any easy fixes. NPR had an excellent program on US gun control recently. The universal judgment was that the NRA has been utterly victorious. They have cleared the board and crushed the opposition. The NRA made Bush president in 2000, and America learned its lesson. No American politician will dare challenge the NRA for at least a generation. I would not encourage challengers, I know when a cause is lost. For now.
Update 4/18/07: I've been thinking about this, of course. Given Mr. Seung-hui's age, the prevalence of disease, and the history we're given, there's a reasonable chance he was schizophrenic. If so, then the most pragmatic preventive actions, given the impossibility of weapon's control in America, is to focus on the disorder of schizophrenia. Should every university professor and staff-person be required to complete a program of study in schizophrenia and major depression? Should universities focus on improved early recognition and treatment procedures, and techniques to manage the very difficult intersection of culture and psychiatric disease? Above all, we need far more knowledge of how to prevent and treat schizophrenia, and we need to know methods to divert the victims of the disease from violent paths.