Virginia Tech (Blacksburg), Columbine (Colorado), Polytechnique (Canada), Dunblane (Scotland), Jonesboro (Arkansas), Nickel Mines (Pennsylvania), and Dawson College (Canada). What do these tragic mass killings of students and school children have in common? The answer is not obvious.

What is obvious, to those of us who look beyond the headlines, is that mass killings were rare when guns were easily available, but have increased as guns have become more controlled.

In the early 20th century, guns were easily available to ordinary people in all civilized countries, including England, Canada, the United States, and France. In many cases, individuals could freely carry them concealed. But all that changed.

Scotland’s 1996 Dunblane massacre, for example, which claimed the lives of 16 children, occurred in a country where, after seven decades of increasing gun controls, it had become very difficult for ordinary citizens to own guns, especially handguns, and illegal to carry them virtually anywhere.

Similarly, the 2006 Dawson College shootings in Canada occurred after 15 years of increasingly rigid gun controls, making it illegal to bear arms even on your own property. In the United States, where the majority of the shooting tragedies have occurred, federal gun controls have increased nearly continuously since the 1960s. None of the massacres was committed by people who were legally allowed to have guns where they committed their crimes, with many of the killings occurring in government-mandated “gun-free zones.”

The truth, as the tragedy in Blacksburg reminds us, is that it is impossible to be totally protected by the police against criminal maniacs, except by turning society into a prison. One important question needs to be asked, though. What if some students or professors had been armed at Virginia Tech, a school where guns are banned?

Interestingly, a bill that would have allowed students and employees to carry handguns on Virginia campuses was defeated in the state General Assembly earlier this year. Virginia Tech spokesman Larry Hincker hailed the defeat: “I’m sure the university community is appreciative of the General Assembly’s actions because this will help parents, students, faculty and visitors feel safe on our campus.” Now what?

When asked at a press conference after the killings what can be done to ensure campus security, Virginia Tech President Charles Steger indicated that there is no way to place a police guard in every classroom or dormitory. That’s so true.

But contrast the horrific Virginia Tech shootings with the January 2002 killings at Virginia’s Appalachian Law School. Within minutes of shooting three people in the dean’s office, disgruntled student Peter Odighizuwa was stopped by two students who had retrieved handguns from their cars. They disarmed the killer and turned him over to the police.

Obviously, when people are intent on massacring defenseless students, there is no sure panacea.

Yet, there must be a reason why such killings haven’t occurred at places like the University of Utah, where people licensed to carry guns can bring them on campus, including university buildings. There might be a reason why the Dawson College killer, who had a car and apparently no special reason to target that specific school, did not go instead to the National Police School, about 100 miles from Montreal, where all students are armed.

We need to take a broader view. Something other than the low probability of being stopped before doing much damage must be at play. Some decades ago, most people, including unruly youths, and perhaps even most criminals, were under certain moral constraints that they were ashamed to break. Since that time, these constraints have crumbled, replaced by post-modernist nihilism and the heavy hand of government.

There have always been self-deluded maniacs who, in order to seek solace and fame, wage destruction. Such was Herostratus who, in 356 B.C., and precisely for this reason, burned the Temple of Artemis at Ephesus, one of the Seven Wonders of the World. However, I seriously doubt he would have killed school children or young women, even if he had had the power to do so.

So long as we tolerate a nanny-state culture of dependency, in which people are treated as children, disarmed and prohibited from protecting themselves, senseless mass killings will continue, and perhaps increase.