Who goes there?

Let’s consider a hypothetical scenario. You live in a rough neighborhood and you recently bought a smart pistol for home defense. You’re lying in bed reading a good book when suddenly there’s a terrible crash downstairs.

Startled, afraid, adrenaline pumping, you drop your book and spring into action. Your hand instinctively goes to the nightstand drawer to retrieve your smart pistol.

But where is your smart watch? To your horror, you realize that you took a shower just before bed and removed the watch out of habit. You left it on the bathroom sink!

You slink quietly out of bed and creep into the bathroom, just as you hear boots crunching on broken glass downstairs. Your hands fumble across the sink counter, feeling for the watch. You find it and put the gun down to secure the watch on your wrist.

Now you need to punch your code into the watch. Do you remember it? Were the last two digits 11 or 32? Or was it 13?

You wince as you turn on the bedroom light. The light will give you away, but you need it to enter your code—or your weapon won’t work.

You put down the gun to type and discover that in the darkness you accidentally put the watch on upside down. You take it off and put it back on again. Fingers trembling, it takes you a few tries, but you finally type the code correctly.

The guy downstairs is rifling through your desk, making quite a racket. It’s only a matter of time until he comes upstairs.

A light on the gun’s backstrap glows red. You’re pretty sure that means the gun is locked, and the light turns green when unlocked. Or is it the other way around? Your mind is racing and it’s difficult to remember. Green could mean “go,” but red could mean “danger, the gun is armed.”

Which is it?

Up ’til now you’ve done everything right, but the gun is still glowing red. It dawns on you that your carpal tunnel has been acting up so you started wearing the smart watch on your left wrist. You’re holding the weapon with your right—and now your hands are far enough apart that the RFID chip doesn’t register.

Do you move your watch to your right hand, or do you hold the gun with your left hand? You’ve never shot the gun with your left hand! Isn’t it funny that you never used your left—

The burglar is coming up your staircase! You must decide!

You grip the gun with your left hand. The light on the backstrap of the handgun suddenly turns green.

That was easy, wasn’t it?

The basics of firearm design really haven’t changed all that much in the past hundred years. Simplicity ensures reliability and ease of use. Not only are there too many conditions to meet before actually use the smart gun, there are too many ways the system might fail.

The ideal solution for gun safety is still the old-fashioned one. $1,788 can buy a Glock 19 handgun, a gun safe that weighs 234 pounds and 800 rounds of nine-millimeter ammunition. You’d have a reliable handgun untethered to an obnoxious security system, a safe that would take three men to lift and keeps children at bay and bullets to shoot.

Oh, and you can wear whatever watch you want on either wrist.

The smart gun is a great idea ... in theory. Wearing a wristwatch and punching in a code might be acceptable to recreational shooters who shoot purely for pleasure. But for people who buy handguns for self-defense and expect to use them in real-world conditions, smart guns are a terrible idea that might get them killed.

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