There have been massacres throughout U.S. history, motivated by race, greed, a combination of the two as in the holocaust and dispossession of the native inhabitants of North America, political ideology or feuding. Ideologically motivated mass murder is ancient and I need not bother to list recent and current examples.
But as far as I can tell, the phenomenon of the lone individual, or occasionally a pair, who suddenly erupt into mass violence with no discernible political motive is not notable in U.S. history until after August 1, 1966, when part-time University of Texas at Austin student Charles Whitman climbed a landmark tower on the campus and killed 14 people, most of them from a sniper's perch on the observation deck. It was later discovered that he had killed his wife and mother before undertaking the massacre. There was an earlier example, the so-called Bath School Disaster in May 1927, in which farmer and school board member Andrew Kehoe, upset over a property tax levy used explosives to destroy the local school in Bath Township, Michigan, killing 45 people. However, this incident had been largely forgotten by the time of Whitman's killing spree. Unfortunately, we didn't have to wait 39 years for another.
Since then, comparable incidents have become frequent enough that they have nearly lost their capacity to shock us. The attack on Friday at Northern Illinois last Thursday was among the comparatively minor examples of the genre. Seung-Hui Cho holds the modern record with 32 killed at Virginia Tech university, but the McDonald's massacre in San Ysidro, on July 18, 1984, in which 21 were killed and 15 injured; and the Luby's Cafeteria massacre in Killeen, Texas on October of 1997, in which 23 people were killed and 20 injured, were pretty impressive as well.
Typical targets, in addition to institutions of higher education and restaurants, have been workplaces, U.S. Postal Service facilities being prominent among them; and elementary and high schools.
The perpetrators are generally young men, but there are exceptions. The Columbine killers were high school boys, and one of the most disturbing incidents was the Jonesboro, Arkansas massacre in which 13 year old Mitchell Johnson and 11 year old Andrew Golden attacked a middle school, killing 4 children and a teacher and injuring 9 children and one teacher. (By the way, under the law in effect at the time they could only be held until the age of 21 and both are now free.) Brenda Spencer, a 16 year old girl, attacked an elementary school in San Diego in January 1979, killing two adults and injuring 8 children. Her actions were immortalized in the song "I don't like Mondays," written by Bob Geldof for the Boomtown Rats. The title represents her explanation for the shooting spree. One of the soi disant disgruntled postal workers was a woman, Jennifer San Marco, who killed six employees at the San Goleta, California mail processing facility where she worked in January, 2006. Sylvia Seegrist killed three people and injured seven at a shopping mall in Springfield, Pennsylvania in 1985, just a short walk from where I was then attending college.
Wikipedia catalogs 42 American spree killers, all of them save Andrew Kehoe post-dating Charles Whitman based on my quick review. A few of these are actually serial killers, which is a somewhat different phenomenon, but most are perpetrators of one-time massacres.
While the phenomenon is definitely an American brand, there have been a few incidents elsewhere: the so-called Aramoana Massacre in New Zealand in which 13 people were killed; the Montreal Massacre at l'Ecole Polytechnique in March 1996, in which the killer exclusively targeted women and killed 14; and the Dunblane Massacre in Scotland in 1996, in which the killer attacked an elementary school, killing 16 children and a teacher.
From a statistical point of view, this is not a big problem. I won't bother to try to come up with numbers, since it would be tedious; the incidence obviously varies wildly and stochastically from year to year; and the definition of a conforming event is not entirely clear. Nevertheless, the average person is clearly much more likely to be killed by a current or former spouse or lover than a berserk stranger, and your biggest risk for sudden death is riding in a motor vehicle. Nevertheless, people are naturally anxious to understand why these events have become such a notable feature of modern American life.
Contrary to the stereotype -- and I don't know where it came from -- that the typical perpetrator was a quiet, polite and nerdy type and that nobody could have seen it coming, most of them were quite evidently troubled prior to their killing sprees. Many had diagnoses of major mental illness, others had histories of minor crime, violence, or disturbing behavior. Charles Whitman had a troubled childhood with an abusive father. He was court martialed as a Marine for minor offenses and did time in the brig. He was abusive to his wife. An autopsy found a small brain tumor, though it is unclear whether this contributed to his actions.
However, there are mentally ill, disturbed and strange people all over the world. Why they have a greater tendency to erupt in mass murder here in the U.S.A. is still an open question. Many people blame the easy availability of firearms, and perhaps that has something to do with it, but there are many other countries where weapons are easy to get where we see other forms of violence, but not this pattern. The Christian Right blames the theory of evolution and general godlessness, but some of the perpetrators were churchgoers: indeed, some of the targets have been the churchgoers' own congregations. Furthermore, as an atheist and firm believer in evolution, I can assure you that I have no violent impulses whatsoever, unlike the Biblical believers who want to execute adulterers and homosexuals. Finally, Europe is far more secular than the U.S. but has far fewer of these sorts of incidents. The Dunblane Massacre is the only example I can think of, in fact.
The bottom line: I don't have a good explanation. Violent movies and TV shows? Pervasive alienation, social isolation, oppressive work environments, failure of community? What do you think?
Update: Maybe Nicole Bell has a partial answer here.
In The Science of Happiness, author Stefan Klein at this phenomena [sic] and comes to some conclusions on a meta-level on what creates happiness in a society and the results might surprise you. He finds that there are three critical standards that must be met: a civic sense, social equality and control over our own lives. The more participatory the democracy, the more equal the social and income distribution among the citizens and the more self-determination (meaning not being forced to do a job you dislike because you have to pay the bills), the happier the society is.
That’s not so scary, is it?