So there you are, cowering under your desk.

From the hallway, you hear the pop! pop! pop! of gunfire, along with the shrieks of the terrified and moans of the dying. The good guy with a gun? Maybe he’s crouched outside the building. Maybe he’s dead in the break room. Whichever, he’s not there. And now, horribly, the doorknob to your classroom begins to turn.

What do you do?

You throw rocks. At least, that’s what you do if you’re a student of the rural Blue Mountain School District in Schuylkill County, Pennsylvania. It came out last week that Superintendent Dr. David Helsel has ordered that each classroom be equipped with a bucket of river stones. “They’re the right size for hands,” Helsel explained to WNEP, a local TV news station. “You can throw them very hard, and they will create or cause pain, which can distract.”

And who knows? Maybe it would actually work. Maybe the kids would get lucky and drive the attacker back. Or maybe a room full of second-graders lob rocks that loop high and clatter harmlessly to the floor and the man in the doorway laughs and kills them all.

One outcome seems about as likely as the other. But to argue the probable effectiveness of Helsel’s rocks is to miss a larger point. Namely, that the very idea is a surrender, a retreat from what ought to be an uncontroversial principle, i.e., that there shouldn’t be a shooter in the hall in the first place.

In that, Helsel’s bucket of rocks is like the proposal to arm teachers and former Sen. Rick Santorum’s dumb suggestion that the best way to respond to mass shootings is to teach kids CPR. None of these strategies, please note, seeks to prevent massacres. Rather, each implicitly asks us to accept that they are inevitable and unstoppable, like natural disasters.

After all, you wouldn’t pass a law against tornadoes or earthquakes, and some gun rights advocates would have us believe it makes just as little sense to try to keep mass shootings from occurring. They ask us to accept the unacceptable as a given.

The problem is, a mass shooting is not a natural disaster, but a human one. Thus, it can be legislated against. Nor is the fact that a law will not be 100 percent effective a sensible reason not to pass it. No law is 100 percent effective. Shall we repeal prohibitions against murder or child molestation because those crimes still occur?

That said, the right has no monopoly on unworkable ideas. Tuesday, the New York Times published an op-ed from former Supreme Court Justice John Paul Stevens arguing that the solution to gun violence lies in repeal of the Second Amendment. This, he says, “would be simple.”

It wouldn’t. In the first place, there’s no reason to believe proponents could muster the necessary support from 38 states. In the second place, the attempt would instantly validate every paranoiac fantasy the NRA has inculcated in its followers, making violent civil unrest inevitable. In the third place, there is no need.

As Canada proves daily, it’s entirely possible to balance gun rights with common-sense restrictions that save lives. Comprehensive background checks and a ban on private ownership of high-capacity magazines and semiautomatic weapons would be good places to start. What we lack is not a way to stop tragedies, but a will.

Reinhold Niebuhr famously prayed for “serenity to accept the things I cannot change, courage to change the things I can and wisdom to know the difference.” But so long as America lacks the second and third, we can never have the first.

At least we’ve got plenty of rocks.

Leonard Pitts Jr. is a columnist for the Miami Herald. Readers may write to him via email at: lpitts@miamiherald.com.

Leonard Pitts Jr.