Get rid of the death penalty in all 50 states

The death penalty needs to go in all 50 states because it is wrong and it costs more money to put someone on death row with all the appeals and the death punishment itself costs money. According to most police captains at major police departments,the death penalty isnt a deterrent for people that murder someone. Innocent people have been put to death because of DNA evidence found way after the accused was put to death. How can we teach people not to kill but we do the same thing right back? The death penalty is inhumane and violates the constitution as cruel and unusual punishment.