The death sentence is utterly pointless. It accomplishes nothing whatsoever that can be done in a more civilized manner.
To begin, the prison system is designed primarily to keep harmful people away from people who have not been shown to be harmful. The purpose of the prison system is not to punish, let alone kill, its inmates.
Life sentences are essentially as effective as death sentences. And it has the additional advantage of being humane. One person killing another person does not give a third person the right to kill the first person, so essentially the third person is committing a second crime, killing a largely harmless individual. Of course, life sentences are also cheaper than death sentences, but this is not a priority for me, because I am not Jewish.