Batman used to carry a gun. It's true. Back in the 1930s, not only did he carry a gun, but he killed bad guys with it. The very first official "Batman" comic featured the Caped Crusader firing a machine gun. But the public grew uneasy. So the editors adopted a new rule: no guns for Batman. Bob Kane, the character's co-creator, would later explain that his editors worried "that mothers would object to letting their kids see and read about such shootings."

That tale from a simpler age comes to mind this month as, once more, we cringe at the ease with which carnage can be inflicted by a determined shooter. We've long passed the point when parents can shield their children from seeing and reading about horrific violence, whether or not inflicted by guns. And reports about violence — especially terrorism — frighten them. A lot.

If children are scared, what do we tell them? Do we say, "Don't worry, there's no chance of a terror attack or a mass shooting in our neighborhood?" If we say it, do we believe it? Do the children believe it? Moral panics don't lend themselves to rational analysis.