In his May 1 letter, "Death penalty is no deterrent," Mark Callow claims that death penalty studies have "repeatedly found no evidence that capital punishment acts as a deterrent." I've been over and over this debate with my friends, family, coworkers, etc., and would simply ask Callow the following question: Has anyone ever committed a second murder after being convicted of a first (in prison perhaps, after an escape, or even after being released)?
The answer to this question is sadly yes, which makes his claim about the death penalty not acting as a deterrent null and void. It most certainly acts as a deterrent to the person who committed the murder -- death being the ultimate deterrent.
If a pit bull kills a child in a park, we destroy that pit bull -- not to prevent other dogs from killing, but to prevent that particular pit bull from ever killing again. If one human murders another human, then he or she is no better than the pit bull and should be destroyed for precisely the same reason: to prevent that particular animal from ever killing again.