I've sat in the same room with murderers who have become harmless people. I would hate to live in a world in which those people were murdered by the state.
Realistically, we're either dealing with people who are capable of reform; or, we're dealing with people who are victims of biology.
If we're killing people who are capable of reform, the death penalty makes no sense.
The best argument for the death penalty is when it comes to the victims of biology - psychopaths, etc. People who were born with a mental problem that will always make them dangerous. Surely, if a defective machine is dangerous to functioning people, you destroy the defective machine. But, isn't there a clash with the reality that we have a "not guilty by means of insanity" aspect to our justice system?
Namely, the only reason that I can see for the death penalty would be to destroy a defective person who is beyond repair. But, it is precisely the defective people who are beyond repair for whom we've carved out a reasonable exception.
If you give the State the narrowest, least objectionable justification for killing people, such as a penalty for premeditated murder, you will nonetheless face the inevitability of people wrongly accused of that act who are put to death.
And that’s simply unacceptable.
Better that a guilty person go free than an innocent person be punished, let alone irrevocably punished.
It’s okay letting the worst people live in jail for life.
It’s not what we want emotionally, but the system that gives us what we want emotionally is lethal to innocent people.