The death penalty is a truly final solution to the problem of a violent criminal. Some people feel it is justified in order to prevent future murderers by the same criminal, while others feel that showing mercy to a criminal and letting him live may encourage a society in which mercy is more common and murders less common.
To execute a killer because we believe he has forfeited his right to live when he took the lives that he took might be justified. But some of the other reasons given to support the death penalty are problematic.
Some people talk not about the killings committed by the condemned inmate, but about possible future killings that may be prevented by the execution. Even if the inmate never leaves prison alive, it is argued, he might kill prison guards or other inmates. So therefore one should execute the killer to prevent this future killing.
But serial killers, the ones most likely to keep on killing, tend not to be violent in prison. And the idea of executing for a future crime is a little weird. It’s like that science fiction movie in which the police had a system to detect future murders, and would pounce on the killer before he had made the kill. It’s impossible for a criminal to prove himself innocent of a crime he hasn’t yet committed. Thus, it is best to focus on the actual murders rather than executing because of future murders.
Another argument is deterrence. If we execute John for killing his wife today, maybe Bill will think twice about killing his wife tomorrow. But deterrence is problematic also. To set the level of punishment for one man based on how other men might react is an injustice.
Just think: if the police were entitled to shoot speeding and careless drivers from ambush that would be a great deterrent- no one would dare break traffic laws if this were the practice. But it would be an outrageous injustice. Death or wounding isn’t an appropriate punishment for bad driving behavior.
On the other hand, if a punishment does not deter, should we leave the criminals unpunished? Some criminals- serial killers, for example- are going to kill in any case until we catch them. Nothing will deter them.
The true purpose of punishment is not preventing future crime or deterring others, but justice. When someone does some illegal killings, they certainly forfeit their rights to life. And if the death penalty is the only way to keep a person out of circulation for good, it may be necessary to permit it.
But if we are to become a society of compassion and of respect for life, it would do no harm to spare the life of those condemned to death by their deeds, provided we are able to keep them locked up.