Charles Steger, the president of Virginia Tech university, was a model of self-control as he told reporters what he knew about the tragedy of “monumental proportions” that left more than 30 innocent people dead on his campus yesterday. Hundreds of his students showed similar self-control during the ordeal itself, scouring the internet for news on friends and the continuing threat to their own lives as police swamped the university and kept them confined to their rooms. Yet one among them had lost all control, taking more lives before dying himself than had been lost in any similar incident in US history. And the shooting will inevitably force back on to the national political agenda anguished questions about whether the country can ever assert collective control over the use and abuse of guns.

These questions could hardly be more urgent. The estimated death toll in Blacksburg, Virginia, rose once a thoroughgoing police search of the university’s dormitory buildings and classrooms got under way. That is double the worst previous death toll in a US campus shooting, and nearly three times the number killed when two teenagers brought unspeakable mayhem to a high school in Littleton, Colorado, in 1999. Each of these mass murders brings personal tragedy and social trauma that observers can scarcely imagine even when bombarded by “as live” TV footage, taken by witnesses on mobile phones if not by news crews. Yet the broader effect, for students, parents and the American psyche, is no less significant even if it is less intense.

On a purely practical level, metal detectors are now standard precautions in high schools, and colleges can be paralysed with scares and lock-downs on the whim of a malicious prankster. Virginia Tech itself had suffered two closures already this month because of bomb scares. Psychologically, the litany of precedents to yesterday’s shootings — there have been 18 incidents in the past decade — can create a sense of acute vulnerability in precisely those places of learning that should be refuges from violence. Philosophically, each successive shooting reopens in more heartrending relief the contest between personal security and personal liberty that the US gun control debate represents.

This contest is more complex than many foreigners allow. Observers from countries such as Britain, with gun control laws so tight that target-shooting teams must practise abroad, may regard massacres such as yesterday’s as a macabre rite of bloodletting that could be staunched if only Congress would turn its back on the National Rifle Association. Yet recent murders in London have forcibly reminded leaders that even the most draconian gun-control regimes cannot deny weapons to criminals and the deranged. Furthermore, the debate in the US is not simply between two opposing bands of Washington lobbyists. It is complicated by myriad state laws, and intensified by the convictions of millions of responsible gun owners who hold, not unreasonably, that most murders are caused by too little personal responsibility, not too many guns.

Yet many innocent students are now dead who might not have been had the Blacksburg gunman faced more obstacles to acquiring his weapon and bringing it to campus. Voters and politicians must acknowledge this, and strive, once more, to prevent it happening again.