Why should we have BOTH life sentences and the death penalty? By definition, a life sentence without parole takes away people's free lives. Upon entry into the system, they are now a permanent financial burden on the state, and there is no possibility that any reform improves their life on the outside, because they are never going outside again. Isn't it, in a system with capital punishment financially gainful, saving in both maintainance and facilities, and ethically equal to kill a man outright as opposed to containing him until you cause his death? -Bunsen

It's apparently really expensive to shepherd a capital case all the way through to eventual execution--some say, much more expensive than life in prison. http://www.deathpenaltyinfo.org/article.php?did=108&scid=7 That aside, there are plenty of other ethically relevant considerations. You can free a prisoner if the conviction is overturned, but you can't bring him back to life. Few of us, when actually faced with a choice, would choose death over life in prison. Nasty as it is, prison is not necessarily intolerable, and it may allow for the pursuit of important aspects of a good life. And even if capital punishment is already used for some particularly horrible crimes, expanding it to others may face objections of the sort people raise against capital punishment in the first place, to do with fairness of application, the value of life, the inhumanity of easily avoidable killing, and the merits of mercy. Even if these objections did not convince you to keep the mass murderer alive, they might...