Only one question matters in the school violence debate: when a shooter is attempting to enter a school, what will be done to protect the lives of students and staff?

Asking what can be done to prevent mass school shootings is a secondary matter. Honest commentators — with the background and experience to know what they’re talking about — should be aware that in a constitutional republic, school shootings cannot be altogether prevented, and that gun control can have no effect. The worst school attack in history — in Beslan, Chechnya, leaving 300 dead and 700 injured — took place in a liberty-restricted state with democratic pretensions. Deterrence is possible, but not with past or current policies; the actual defense of the school during an incident is the heart of the debate.

At enormous expense, schools can be hardened, which may help to deter some potential killers, and which may slow down, to some degree, less intelligent and prepared killers. Unfortunately, “slow down” implies seconds, not minutes. Equally unfortunate: the money necessary to harden schools to the point of truly credible deterrence that could slow or stop killers to any meaningful degree is not available during the Obama economy.

Just recently, it was revealed that the Sandy Hook Elementary School killer needed only five minutes to shoot his way into the school and murder 20 children and six adults before killing himself. This fact is fodder for those wishing to ban “assault weapons” and standard capacity magazines so that future killers with five minutes will require a few seconds longer, or might only be able to kill 20 rather than 26. They miss the point, and many intentionally ignore more sensible proposals.

Former Navy SEAL and current educator John A. Czajkowski proposes a solution that embraces the recommendation of the NRA: place armed security in every one of the 100,000-plus American schools. However, he generally opposes the arming of school staff:

Although I grew up very comfortable with the responsible use of firearms as a boy and then later professionally, I still can’t support arming teachers first when there are still so many other more proactive opportunities for improving our security. Arming teachers is far down my list of recommendations for improving security, per balancing return on investment and risk assessment. Although I am entirely comfortable with the idea at a personal level, the difficulty of applying Kant’s universal imperative makes me hesitate to adopt an armed teacher paradigm.

Only one policy can credibly deter school shooters, will cost little or nothing, and will provide the maximum chance to limit — or even to eliminate — the loss of life when an attack on a school occurs: arming school staff.

When school design, security cameras, hardened doors and glass, magnetic door locks, and every other security measure have failed — as they did at Sandy Hook — and when a killer is seconds from firing, what is that school prepared to do at that moment to prevent any loss of life? Unless they are taking affirmative steps to arm staff so multiple people will always be present and prepared to immediately engage an armed attacker, the schools tacitly admit they are willing to accept a death toll of some size. This, in exchange for “feeling safe” rather than being safe.

NRA chief Wayne LaPierre and Czajkowski’s approach — using trained, armed personnel focused on school security — is not unreasonable, but it is impractical and embraces several faulty assumptions.

La Pierre would even demand federal funds for the purpose. Even so, some schools — usually larger high schools and some middle schools — do have school “resource” or “liaison” officers, who are usually certified law enforcement officers provided by local agencies.  Some schools share an officer from time to time, but most schools have none. This is so for practical and insurmountable reasons. Moreover, those few officers do not function as most of those supporting this concept believe.

These officers are essentially small-town police, responsible for all law enforcement functions in and around their assigned schools. They are generally present only during normal school hours, but must be absent for a wide variety of reasons: court, job-related errands, transporting arrestees, mandatory training, medical appointments, and vacation. At those times, they are virtually never replaced, and they are seldom present for extracurricular activities.

Further, it is not their job to principally focus on building security. And because there is only one of them per school — if that — the chance they will be present at the time and place an attack occurs is small. If no one else is armed, they are better than nothing, but are not the answer.

Most schools don’t have these liaison officers and never will; it’s too expensive. Their salaries, whether paid by their agency, their school, or some combination, come from the taxpayers, an increasingly scarce funding source. Affordably putting more of them in schools is wishful thinking.

As an educator, I deal with colleagues who recoil at the idea of armed police officers in school, as though the mere presence of authority, particularly armed authority, somehow poisons a mystically pristine educational atmosphere. I have heard others argue that teachers are untrained and unqualified to carry firearms, and as such would be tempted to misuse them, or would be more likely to harm themselves, or others, or to be shot by the police in a school attack. I have heard some argue that students will steal teachers’ guns.

However, the most fervent argument I’ve encountered — and only after the Newtown shooting — suggests that teachers must focus 100% of their energy and attention exclusively on teaching. Therefore, they cannot be expected to assume the same duties as school liaison officers, including engaging and stopping school shooters.

Some have gone so far as to suggest that teachers would be particularly bad at even recognizing that a shooting was happening, so oblivious to their surroundings does teaching make them.

This misconception is a related to the idea that anyone carrying a gun on school grounds must be trained to the same level — and must assume the same focus and duties — as a certified police officer, or else they are a tragedy waiting to happen.

No. Armed school staff should have precisely the same duties and responsibilities as any citizen with a concealed carry permit.

They are responsible for keeping their weapon safe, secure, and concealed, and on their person at all times. A handgun locked in a desk or in an armory in a principal’s office suite is of no use to a teacher meeting an armed killer in a hallway or on a playground.

Above all, they will know to use their handgun only in circumstances where it is necessary to stop the imminent threat of serious bodily harm or death to themselves or others. And that is all.

Police officers undergo lengthy and rigorous training because their jobs encompass far more than this simple directive, whereas armed citizens and teachers need know only two primary things: the law relating to the possession and use of deadly force, and how to shoot straight.

Additional training along these lines is desirable, but if required, will prevent some teachers from being able to save their lives and the lives of students.

The entry qualification should be precisely the same as for any concealed carry license holder. Teachers should in fact be already almost entirely qualified, for like license holders, they have been fingerprinted, photographed, and undergone extensive background checks.

Unlike license holders, they must have at minimum a bachelor’s degree, and must undergo additional extensive testing. The only qualification most teachers lack would be any state-required training course or shooting qualification.

A cornerstone of this policy must be correct publicity. Making the public aware a given school district allows and encourages its staff to carry concealed weapons confers on every school, whether anyone is carrying or not, the benefits of deterrence.

Properly chosen by and for individuals, concealed handguns are quite invisible: this is another strength of concealed carry. Because no criminal can know who is carrying a handgun, they must assume that everyone could be. Just about anywhere in America except schools, this is also the case.

Consider the cognitive dissonance of those who argue that teachers can’t be expected to take extra time to qualify for concealed carry: recall that they already spend hours on “run and hide” drills, hiding students behind locked and easily breached doors to fearfully wait and hope that a killer will not find them. This dependence on the lack of competence and marksmanship of madmen (as well as their mercy) is not a strategy.

Consider too those who argue that teachers aren’t smart enough to understand what is happening, and will thereby shoot innocents. When a school attack occurs, and this was very much the case at Sandy Hook Elementary, the victims knew exactly what was going on. When the killer was shooting his way into the school, if one or more staff had been armed he could have been immediately stopped. No one had to die that day; no one has to die in any school.

The idea that teachers’ guns will be stolen and misused, while possible, is hardly a reasonable argument for failing to protect lives: all of life is a matter of balancing benefits and risks.  Fortunately, there is an experience model. Utah has for many years allowed teachers to carry handguns: there has not been a single instance of such misuse. Texas also allows it, and South Dakota has recently passed a law allowing on-campus concealed carry. Other states are considering legislation.

What about the argument that teachers can’t shoot straight?  It’s not well-known, but the police are hardly firearm experts. They are required to qualify only once a year on less-than-demanding courses of fire with equally non-demanding qualifying scores. Many citizens surpass the police in shooting skill. Wearing a uniform and badge does not confer magical shooting skills beyond the capability of the private citizen.

Consider the plight of teachers holding concealed carry licenses. Off of school property, their inalienable natural right to self-defense is operative. They may protect the lives of themselves and their children, at home and anywhere they may be. But step on school property, and due to those that claim to be most concerned with protecting children, they and their children lose the affirmative means to preserve their lives. Are the lives of teachers and children worth less on school property than off?

In any school attack, two things matter most: time and distance. Armed killers have the advantage of both. Every second matters, and time is not on the side of victims or the police. At Newtown, a life was lost approximately every 11.5 seconds. From the time the killer shot his way into the school until he shot himself, only five minutes elapsed, but it took the first police officer 20 minutes to arrive. This is normal, and must be expected in the future: in virtually every school shooting, the police have had no active role in stopping the shooter.

Even if the Newtown police had arrived within five minutes, they still would have had no role in stopping the killer.

If there is no one present to immediately engage and stop a school shooter, the only factors determining the eventual body count will be the killer’s lack of marksmanship and dumb luck.  Depending on the mercy of a madman, or luck, for the lives of innocents is quite insane. Even an armed teacher running from one hallway to the next to engage a shooter is far preferable than waiting for police that will virtually never arrive in time, and will be summoned only after some children and teachers are already wounded or dead.

One may conjure any number of objections to allowing armed teachers and school staff, but every possible objection can be addressed with proper — and inexpensive — procedures and training. The undeniably positive benefits of armed teachers, people always present and always ready and able to stop armed killers, greatly outweigh any potential objection. Which possible negative consequence outweighs the preservation of innocent lives?

Consider Virginia Tech spokesman Larry Hincker, commenting on the defeat in the legislature — only a short time before the attack — of a bill that would have allowed students and faculty to carry firearms on campus. He said:

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.

Signs, doors, locks, and good intentions do help some to feel safe, but teachers and staff ready and able to stop killers is actual safety.