Guns. Booze. War. Abortion. Voting. How Old Is Old Enough?

It is too soon to know whether the Parkland massacre will clarify public attitudes about guns. But we can safely bet it will do nothing to clarify public attitudes about maturity. If anything, the episode has only muddled things further.

In the aftermath of the Valentine’s Day slaughter, some Parkland students have transformed into gun-control activists. This has elicited sympathetic coverage in the establishment press, polite criticism from the conservative press, and vicious attacks and loony conspiracies from the troglodyte right.

Nobody is suggesting the students qualify as experts on public policy. The respectful hearing they have received has more to do with their moral authority as young, traumatized, and idealistic survivors of a horrific event. (And, to be frank, it helps that they have staked out a position with which most of the media already agree.)

At the same time, the shooting itself—carried out by a 19-year-old—has elicited proposals to raise the age at which a person can buy a rifle to 21. The notion that teenagers can be wise enough to teach their elders about firearms, but never wise enough to own them, is just one of the ways in which American attitudes about adolescence lack explicable precision.

The U.S. already has raised the drinking age to 21. But as is often noted, you need be only 18 to enlist in the armed forces—i.e., to volunteer for missions that could entail not only losing your own life but taking others’.

The age of enlistment offers two rationales for not raising the age at which someone can buy a gun. If you’re mature enough to enlist, goes one, then you’re mature enough to own a gun. (Rebuttal: Enlistees’ lives are regimented to a ridiculous degree. Unlike civilian 18-year-olds, they’re not being given free rein.)

The second rationale holds that if you are old enough to sacrifice your life in America’s defense, then you should have access to all of America’s constitutional rights. Indeed, that was largely the rationale behind lowering the voting age once the age of conscription had been lowered.

Of course, nobody ever died because somebody picked up a ballot in a moment of anger. Nor has an improperly or accidentally used ballot ever killed anyone. People die from gunfire under those conditions all the time. So there might be some sense in leaving the voting age at 18 but raising the age of access to devices that can kill.

Except that most states let teenagers drive without supervision at age 16—and sometimes earlier—even though the Insurance Institute for Highway Safety points out that “teenage drivers have the highest crash risk per mile traveled.” In fact, the Institute says, the fatal crash rate for drivers age 16-19 is “nearly three times as high as the rate for drivers 20 and over.”

So teens are mature enough to handle 3,000-pound machines despite the great risk of harm that entails. Yet colleges across the country strive to make themselves “safe spaces” not only for teenagers but for young adults as well—by imposing speech codes, warning students against “microaggressions,” and caterings to those whose tender feelings are often theatrically wounded by the mere presence somewhere on campus of people with whom they disagree.