I agree with the self-defence point. If someone is coming at you with intent to take something of yours it is instinctive to try to prevent them. Forget the 'reasonable force' clause in British law - you do not have time to think in this situation - you just act.
So we have now introduced another factor into the arguement - What in the States I believe is called 'Justifiable Homicide'. Is this correct, btw, or is that just in the movies?
I am sure that the statistics will show that a very high proportion of murders are without pre-conception. That they happen in the heat of the moment, a 'crime of passion'.
Forget the Hindleys and Bundys, Shipmans and Mansons for a moment. If something is done 'in the heat of the moment' no penalty will prevent it from happening. Neither should we use the death penalty for what boils down to, effectively, loosing your temper. I have seen plenty of people right here in this cafe guilty of that crime.
OK - so if we now accept that the death penalty is neither deterent or fitting punishment for crimes of passion or justifiable homicide we can turn our attentions to the previously mentioned mass-murderers, psyco's and otherwise deranged individuals.
We now have two types of murder and therefore two types of murderer. If the death penalty is to be applied to one and not the other how do we decide which?
Is the gunman who massacred the children in a schoolyard an evil demon or someone genuinely ill enough to believe they were right? Is the wife who killed her abusive husband in the heat of the moment a victim herself or a devious, lying cold-blooded killer?
No-one can know for sure. No judge. No psychiatrist. No twelve good men and true. There is, therefore, always an element of doubt.
And where there is an element of doubt we cannot use the death penalty.
Only my views
Dave the Gnome