Why the Death Penalty is Unethical and should be Abolished

I heard this quote blurted out the other day: "If you go on a killing spree like Ted Bundy then you need to be killed." I have also heard the more generic statement: "If you murder someone you should be killed in return." Here is the thing though--both of these eye for an eye sentiments are not only unjust but also immoral . If somebody commits the heinous crime of murder, and you in turn murder them as "due punishment" for that murder, you are technically committing the *exact same crime as they have. You cannot claim you are about justice when you turn around and commit the very same crime the criminal committed as punishment against him/her. The reason, I hope, should be obvious. By this logic you too must be killed for the murder of the murderer. The person who kills you for having killed the murderer who killed someone else will also be forced to face the same inevitable fate. The cycle only perpetuates more murde...