[kiba]

If the death penalty is so rare and never administered, then its theoretical deterrence value is going to be zero.

There's no point of keeping around an inhumane law if it doesn't save anyone and actually contribute to the death toll.

Likewise, with the march of science and technology, I expected we will revisit the question of the role of punishment in reducing and preventing anti-social behaviors.

[em-bee]

the death penalty is not about deterrence, but about adequate punishment for the crime. if you murder someone you have lost the right to your own life. but in my belief the death penalty should only be applied if the defendant voluntarily admits their guilt without coercion regardless how obvious the evidence is otherwise. this removes any deterrence effect because a defendant can always plead not guilty.

[Ichthypresbyter]

It has deterrence value in edge cases that almost never happen.

Possibly the best example is treason in wartime. Life imprisonment isn't a deterrent there- people usually only betray their country in a war if they believe that the other side will win, in which case they will be set free and given a medal.

But I agree with you outside that specific edge case.