Once we engineered a selective shutdown switch into the Internet, and implemented a way to do what Internet engineers have spent decades making sure never happens, we would have created an enormous security vulnerability. We would make the job of any would-be terrorist intent on bringing down the Internet much easier.

Computer and network security is hard, and every Internet system we’ve ever created has security vulnerabilities. It would be folly to think this one wouldn’t as well. And given how unlikely the risk is, any actual shutdown would be far more likely to be a result of an unfortunate error or a malicious hacker than of a presidential order.

But the main problem with an Internet kill switch is that it’s too coarse a hammer.

Yes, the bad guys use the Internet to communicate, and they can use it to attack us. But the good guys use it, too, and the good guys far outnumber the bad guys.

Shutting the Internet down, either the whole thing or just a part of it, even in the face of a foreign military attack would do far more damage than it could possibly prevent. And it would hurt others whom we don’t want to hurt.

For years we’ve been bombarded with scare stories about terrorists wanting to shut the Internet down. They’re mostly fairy tales, but they’re scary precisely because the Internet is so critical to so many things.

Why would we want to terrorize our own population by doing exactly what we don’t want anyone else to do? And a national emergency is precisely the worst time to do it.

Just implementing the capability would be very expensive; I would rather see that money going toward securing our nation’s critical infrastructure from attack.