Roy Adler and Michael Summers of Pepperdine University have this op-ed in the Wall Street Journal on their new study on death penalty deterrence.
The conclusion that each execution carried out is associated with the saving of dozens of innocent lives creates an extraordinarily difficult moral dilemma for those who campaign against the death penalty. Until now, those activists could look into the eyes of a convicted killer, hear his or her sad story, work tirelessly to set aside the execution and, with that goal accomplished, feel good about themselves for having "saved a life." These data suggest that the moral equation is not nearly that simplistic.
It now seems that the proper question to ask goes far beyond the obvious one of "do we save the life of this convicted criminal?" The more proper question seems to be "do we save this particular life, at a cost of the lives of dozens of future murder victims?" That is a much more difficult moral dilemma, which deserves wide discussion in a free society.