“You don’t have to be the hero.”

That, John Castillo told NBC News Wednesday, is something he had advised his 18-year-old son, Kendrick. If ever a shooter invades your school, son, don’t try to confront him, don’t take the risk. But Castillo said Kendrick had other ideas, telling his dad that he would not hesitate to defend other people’s lives.

As the world now knows, Kendrick was as good as his word. When two of the latest in this country’s seemingly endless line of armed maniacs descended upon the STEM Schools Highland Ranch near Denver, witnesses say Kendrick rushed him. Some other boys managed to disarm him. In the melee, one of the students, Joshua Jones, was wounded. And Kendrick was killed.

The young man whose father told him not to be a hero became exactly that. But he never should’ve had to.

That goes also for Riley Howell, a 21-year-old student who died seven days before Kendrick, tackling a gunman in a classroom at the University of North Carolina Charlotte. And it goes for 60-year-old Lori Gilbert-Kaye, shot and killed 10 days before when she stood between her rabbi and a gunman at a synagogue near San Diego.

All of them heroes, yes. But in a saner nation, they might not have had to be. Indeed, in a saner nation, they might still be alive.

“Don’t blame the gun.” That’s what gun-rights advocates always say in moments like this. And OK, fair enough. Let’s not blame the gun.

But can we not blame this nation’s insistence on easy and unfettered access to the gun? Might that not have the tiniest bit to do with the fact that gun violence is rampant here?

Instead of dealing with that causality, gun people ask us to take gun violence as some immutable fact of life, some intrinsic component of freedom. That’s nonsense, but it’s nonsense they have to embrace because to do otherwise is to face an untenable truth.

People are dying for nothing.

For some fantasy of rugged self-reliance. For some shortcut to macho. For some terror of the dark Other standing at the bedroom window.

For nothing.

“There is no reason why on the street today a citizen should be carrying loaded weapons.” So said no less towering an icon of conservatism than Ronald Reagan. Of course, he said it in 1967, before conservatism lost its mind — before Florida gave guns to teachers and Iowa gave them to the blind, before cause divorced effect and reason became an anachronism, before 6-year-olds developed PTSD and mass murder became normal.

If it is true, as Martin Luther King once said, that, “No lie can live forever,” then there must eventually come a day when we face the truth of what we have allowed. One wonders what the death toll will be by then.

Meantime, in place of truth we have heroes. Their selflessness and sacrifice, their willingness to do what must be done, whatever the cost, rightfully inspire us.

But they diminish us, too. Because, inadvertently highlighted in the reflected glow of their sacrifice is the bitter truth of how pusillanimous, how cowardly, how chickenhearted, is the nation that required sacrifice of them to begin with, the nation that lets people die for nothing because it cannot muster the moral fortitude to restrain its own carnage.

In Denver, they held a vigil for Kendrick Castillo. Riley Howell, an ROTC cadet, was buried with military honors. An overflow crowd paid tribute to Lori Gilbert-Kaye. And it is well and fitting that we do such things. But there is a better way to honor these martyrs’ courage.

By finding some of our own.

— Leonard Pitts is a Pulitzer Prize-winning columnist for The Miami Herald.