For those of you not in the US might I suggest that you good folk research House vs Bell. It involves evidence, including DNA as well as the issue of convictions based on that evidence.
Once we have perfected a way of reversing and recinding the death penalty, I will be more likely to support its application. Once we can come back, years or decades after putting someone to death and reverse all that has been done it might be a viable option.
Aslan is not a Tame Lion