first of all... I think the number of people who have not committed crimes that are awful is BECAUSE of the death penalty is higher than those who "fight to the death" (LOL) to avoid capture. I think life in prison or the death penalty has about the same effect once they are surrounded by the police.
My proof is that I have seldom seen anyone who did not fight the death penalty once given. They are afraid of it so it is a deterrent.
As for those 'wrongly convicted' well... show me one case that is proven without a doubt that is not from the almost 100 years ago. And.. show me one that didn't deserve it even tho maybe DNA got the fucker off on that particular one. Take a look at the rap sheets on these model citizens.