The Newtown tragedy cries for a change in public policy, but if we’re serious about wanting to reduce the carnage from random mass shootings, stiffer gun control laws are no answer. Marginal gains might be had from, say, regulating gun show transactions or large round magazine sales. But as study after study has shown, no credible correlation can be drawn between such laws and gun violence. As in most such cases, the Newtown guns were legally obtained, after all.

Our mental health policies doubtless need attention, but that’s a complex issue, fraught with civil liberties implications — like gun control itself. Self-defense is one of our oldest, most basic rights, as the Supreme Court held when it ruled that the Constitution protected the qualified right of individuals to own guns.

That brings us to a practical answer that does have promise. The best protection against an unstable person with a gun is another person with a gun. That’s why the police have guns. But they can’t be everywhere. As they raced to the Sandy Hook School, or Virginia Tech, or Columbine, the killing of defenseless people continued. Yet as David Kopel shows in the Wall Street Journal, we have many examples, as recently as last week at a mall in Oregon, where ordinary citizens with handgun permits saved many lives. We’ve learned that the Sandy Hook principal “lunged” at the killer. Suppose she’d shot him. How many children would be alive today if she had?

Gun-control advocates often recoil from such suggestions. Perhaps they believe we can confiscate 300 million guns from law-abiding citizens. That won’t happen. What we can do, if we’re serious, is reduce the risk with trained and armed people in otherwise “gun-free zones.” Do I wish it were otherwise? Yes. But it’s not. That’s the real world.