I have never had a problem with the death penalty, on paper anyway. If our prison system is based on the idea that a prisoner should be reformed and rehabilitated, that they should become model citizens who contribute to the overall well-being of our society, then the death penalty makes sense.
There are some individuals who cannot be rehabilitated. Men and women like Jeffrey Dahmer, Aileen Wuornos, Ted Bundy: they cannot change. They will always want to kill. They will always seek it. They see nothing wrong with their actions. Since there is no chance of rehabilitation, there is no point in trying. Why not put them to death for their crimes?
There is the moral issue, the notion that the State has reduced itself to the level of the killer by executing them. This holds no real rational weight. Unless the State picks an individual at random, tortures them, murders them and then desecrates their remains, the State has not stooped to the level of, say a Jeffrey Dahmer or a John Wayne Gacy.
An execution is a pragmatic solution to a difficult problem: An individual is killing citizens. The individiual will always be a threat to the populace. Therefore, the individual must be removed from the populace permanently. Rather than expend a great deal of resources keeping this individual alive in the prison system, the individual is executed: saving time, money and fixing the problem.
On paper anyway. Several studies show that it’s cheaper to keep a prisoner alive for the duration of their lifetime, than it is to put them to death. So, in actuality, greater resources are expended while sentencing, holding and than executing a prisoner, than while sentencing and imprisoning them for life. Pragmatically speaking, the death penalty doesn’t make logical sense.
There are further problems with the death penalty in a real world setting (potential for the wrong individual to be put to death, disturbing disparities between the sentencing of criminals of different races), but I’m bored.