Richard, I suppose that is the second most used argument against the death penalty, and I certainly would not want to execute a person who did not do the crime. However, the long appeals process, and other legal safeguards make this an extreme rarity. I believe human life to be so important, that the only way to adequately punish the wanton murder of a person, is to take the life of the murderer. Your argument is overbroad owing to the the fact that wrongful execution of an innocent is extremely, perhaps infinitesimally rare; there is no 100% in any human endeavor or creation. Life would come to a standstill if we required 100% certainty in our actions.

I'm guessing the most used rationale for non-execution is that it is considered considered, by antis, to be state murder; it is not. Without the death penalty, there could well be more personal revenge killings and vigilantism, and perhaps even family/clan feuds, because the families of victims do not feel their loved one did not get justice.

Finally, murderers who are given less than death sentences have been known to kill whilst in prison, both other prisoners and guards. Some have escaped and murdered again, and some are paroled and murder again.

It is a pleasure, Richard, to exchange ideas with you.