To stop mass killers, we should let people like off-duty police and security guards carry concealed weapons.

The recent senseless killings in Isla Vista, California of six college students at the hands of an obviously troubled 22-year-old Elliot Rodger, who then killed himself before he could be apprehended by the police, has provoked another call for more gun control. Nancy Pelosi’s remarks are typical in the current outrage: “The tragic and horrific shooting in Santa Barbara last week is the latest in a series of reminders of the urgent need to act.”

Before turning to the merits of the argument for more gun control, it’s important to begin with the facts of the Rodger killings, which Pelosi described cryptically, but wrongly, as a shooting. A full account of the situation makes it clear that Rodger’s first three victims died of knife wounds and that his last three victims were killed by guns. This is an important fact to consider. Today, unfortunately, many people have the perception that the vast majority of murders are done by guns. Reliable records that go back many years for all homicides paint a very different picture from the common perception of gun violence that lies behind today’s anguished calls for stricter regulation. Many murderers use knives and other blunt instruments to kill others, yet no one has any proposals for how to regulate those. Just look at these numbers:

Let’s consider three data points from this table, those for the years 1965, 1993, and 2011. They illustrate the general trend. The number of murders in the United States increased from 8,773 in 1965 to a high of 23,180 in 1993. Then there was a steady drop in the overall rate of killings, which fell to 12,664 in 2011. These figures have to be adjusted by population to obtain the relative frequency of killings. Thus in 1965, the rate of murder was 45.1 per million on a population base of 194. 3 million; by 1993, that rate had nearly doubled to 89.2 per million, off a base of 259.92 million. The comparable figures for 2011 was 40.64 per million on a base of 311.59 million—which makes it less than half the rate in 1993, and lower than the 1965 rate.

It is equally instructive to sort the killings by the instrument of death. In 1965, the percentage of gun killings was 57.2 percent, most of which were by hand gun. By 1993, the peak year, the percentage of gun deaths rose to 69.6 percent. By 2011, that percentage had dropped slightly to 67.7 percent. Of equal importance, were 2,021 knife deaths in 1965, which accounted for about 23 percent of all murders. That percentage declined to 12.8 percent in 1993, and rose slightly to about 13.3 percentage in 2011. The number of killings by bare hands and blunt instruments was significant in all periods, but, in total, accounted for somewhat less than guns in all three years.

There are three lessons that should be drawn from these figures. The first is that the gun crisis, while always serious, cannot be described as “urgent” if that term is meant to imply that the current situation is somehow worse than it was in previous periods. The blunt truth is that the overall situation has gotten better not worse, as the general decline in crime rates are also reflected in the murder rate. Second, the rate of non-gun deaths raises serious problems in the United States, which Rodger’s three knife killings sadly confirms. Third, it is very hard to come up with any single explanation that explains the overall decline in murder rates, in which deaths by guns falls substantially, but less rapidly, than deaths by knives, blunt instruments and hands, neither of which are amenable to regulation of any sort.

What Should be Done?

The landscape looks even odder one when takes into account the number of deaths that are a result of mass killings. These low probability events account for only a tiny fraction of gun deaths, which Dr. Richard A. Friedman in an excellent New York Times column reported stood at 0.15 percent for 2012. Indeed, the tragedy in Isla Vista is not considered a mass killing according to the FBI definition: a mass killing (as opposed to serial killings) requires four deaths, one more than the deaths by guns in Isla Vista. But even lumping together, as we should, mass killings with shooting sprees, gun control advocates are mistakenly offering a series of troubling proposals based on these rare mass killings. Two of the most common are stricter criminal consequences and more regulations of guns.

Better state and federal prosecution. In principle, it is hard to be opposed to this improvement if it comes at a low enough price. But it is critical to ask prosecution for what. Rodgers committed suicide after killing others. So did Adam Lanza after he killed his mother, 20 children, and six other adults at Sandy Hook. One 2005 study estimated that about 1,000 to 1,500 murders and homicides were paired with suicides, which is again consistent with the Rodger and Lanza stories. The FBI refers to these outcomes as “suicide by cop.” For killers prepared to take their own lives, countermeasures seem hard to design The usual theories of deterrence work well with rational actors most of whom never want to kill anyone anyway.

Better gun registration.This proposal intends to keep guns out of the hands of potential criminals in the first place. Right now the House of Representatives has approved a program for Congress to implement a National Instant Criminal Background Checks System (NICS), which would allow for the coordination of data about potential gun purchasers on a nationwide basis. The supporters of the program insist that the rapid collation of state data will make background checks more effective. But so what? Even if the data is accurate when filed, it will plug just one hole in a leaky boat. Nothing says that future murderers will acquire their weapons directly from licensed dealers. They may own guns already, or acquire weapons through a friend, or steal them. Indeed they could shift to knives. No registration data system can limit these common possibilities.

Nor can any record-keeping system keep track of the change in mood and motivation of people after they acquire their weapons. Elliot Rodger had a clean record when he legally purchased his gun. Would a national registry have exposed him at the time of his purchase? Other schemes to limit gun purchases, such as Chicago Mayor Rahm Emanuel’s proposal to limit gun purchases to one a month, are every bit as porous. In the case of Chicago, people can still buy weapons outside the city limits. Finally, banning assault guns is useless since these weapons are involved in only a tiny fraction of killings.

No legislation that hopes to keep guns out of the wrong hands can work because we don’t know whose hands those are. Friedman notes that there is precious little overlap between the population of insane people and dangerous people: the overwhelming fraction of dangerous people are not insane, and the overwhelming fraction of insane people are not dangerous. Worse still, insane people are, as it were, not crazy. They are capable of disguising their intentions as they work up their long term plans with meticulous precision. An overburdened health system has to cope with potentially millions of suspects. The suspect has to manage only his own emotions.

A Modest Proposal

One reason why mass killers succeed is that they know that it is unlikely that they will face any armed resistance. The effort to create sterile environments keeps all guns, but one, out of schools, churches, movie theaters, and universities. Gun killers take advantage of these conditions. The question is how to neutralize their edge.

One solution involves calling for more guns, not less, in the general population. Arming the general population carries with it enormous risks. But there are literally thousands of individuals who are trained in the use of firearms because of their police, military, or security training. The Israeli policy for dealing with terrorist threats combines strict gun laws for ordinary people with extensive gun use by professionals. Allowing many, and even requiring, certain public officials to carry concealed weapons could create a level uncertainty that might deter mad killers from wreaking harm. The deterrent in this case is cheap to put into place, and will work even if psychologists are incapable of identifying potential killers in advance.

No one can claim special insight into the psyche of a madman. But we know that the suicidal mind is prepared, even eager, to die after he kills others. But he does not wish to die alone. If we allow some members of the general population to be armed, a madman could be stopped before taking others down with him.

Richard A. Epstein, Peter and Kirsten Bedford Senior Fellow at the Hoover Institution, Laurence A. Tisch Professor of Law at New York University, and senior lecturer at the University of Chicago, researches and writes on a broad range of constitutional, economic, historical, and philosophical subjects. He has taught administrative law, antitrust law, communications law, constitutional law, corporate law, criminal law, employment discrimination law, environmental law, food and drug law, health law, labor law, Roman law, real estate development and finance, and individual and corporate taxation. His publications cover an equally broad range of topics. His most recent book, published in 2013, is The Classical Liberal Constitution: The Uncertain Quest for Limited Government (2013). He is a past editor of the Journal of Legal Studies (1981–91) and the Journal of Law and Economics (1991–2001).