I think a basic cause of the philosophical disagreement re: capital punishment is caused by one's perception of what the result of a crime should be.
As a society, are we looking to rehabilitate or punish the criminal? Obviously, if it is rehabilitation, then capital punishment doesn't work. As punishment, however.... Well, it's pretty definitive.
Here in Canada, from a political standpoint, the society seeks to rehabilitate the criminal which is an admirable goal. I don't know the recidivism rate here but I'd guess that the majority of criminals do backslide upon release from jail. So it is a flawed system.
I also feel, though, that capital punishment is flawed. There is always the chance that an innocent person could be executed and there are always cases that provoke debate on both sides of the fence - Tookie Williams, for example.
Everything I've read about Tookie Williams states that he turned his life around in prison. He preached about the dangers of gang life to young people and tried to make his life positive - or as positive as possible in jail. Yet he was still executed. Obviously the desire for punishment outweighed a desire for criminal rehabilitation in that case. Not a positive outcome in my opinion.
On the other hand, people like Bundy, Gacy or Bernardo (one of Canada's own serial killers) who are sociopaths who have no desire to stop torturing and killing victims, it's hard to imagine any possibility for rehabilitation in their cases. And in Bundy's case, he managed to escape from custody to continue his crimes.
In a society dedicated to punishment, those who have redeemed themselves, like Tookie Williams, will be executed anyway. But in a society dedicated to rehabilitation, those who continually condemn themselves like Ted Bundy may end up with far more chances than they deserve, and may also end up doing far more harm in the long run.
It's an interesting quandary.
You'll notice that I've not said whether I'm in favour of capital punishment or not. That's because I really don't know. My head says 'no, absolutely not' but in my heart, when I hear of someone like Bundy or Gacy being executed, I can't bring myself to feel sorry about it.
Irene