Killer Argument

I'd never actually understood the logic to work that way...

I've heard "I doesn't make sense to kill people to show people that killing is wrong," often enough that it's just another cliché, and I don't think much about it. In large part because I'd always found the logic of the slogan to be weird. The purpose of punishments isn't demonstration, but deterrence.

In any event, I'm not sure that the logic works even if one takes it at face value; because courts routinely hand down penalties that would be crimes if anyone else were to impose them themselves, sometimes for the same sorts of behavior. Let's take the obvious one: Were I to forcibly bring someone to my home, find them guilty of some infraction or another, and lock them in a spare bedroom for some amount of time, I would, when caught... go to jail/prison. The state would, basically, imprison me for imprisoning someone to show that imprisoning people is wrong. But I've never heard someone argue that logic as a reason that prisons should be abolished. Of course, the world is a big place, and I'm sure that the argument is out there somewhere, but I haven't encountered it yet. The closest I've come is the libertarian Non-Aggression Principle, but it more or less argues against any after-the-fact punishments that require the use of force, since it only sanctions force to stop rights abuses.

There are other arguments against the death penalty that take into account the unique (or somewhat unique) characteristics of the practice, but in this particular case, the argument being made seems like a special pleading.