Now let's talk about the deterrence issue. Deterrence is hard to measure, but there is certainly more evidence to show that the death penalty is not a deterrent. In fact, the conclusion should be pretty damn clear.
Dusting off the old criminal justice notes from college, the theory of deterrence posits that in order for any punishment to be an effective deterrent, the punishment must be swift, certain, AND severe. All three must be present. Of course, there is no perfect deterrent, partially due to our justice system (rights of the accused, due process, cruel and unusual punishment, etc). Swiftness dictates that you are quickly punished after the crime occurs, which almost never happens, and in fact it is rare to even be caught quickly after committing a crime. Certainty of punishment would mean that you are certainly going to get caught and punish if you commit the crime, but we all know that a large number of crimes, including murders, go unsolved. In terms of a severe punishment, it doesn't get any more severe than the DP, but without the other elements of swiftness and certainty, deterrence isn't going to happen. Then of course you can argue whether or not life in prison is on par with DP in terms of severity, or if it is a big enough difference to matter in terms of deterrence. I'd argue that life in prison without possibility of parole is pretty severe.
To reinforce this point, if the death penalty was an effective deterrent to committing murder, you might expect that the murder rates in states that use the death penalty would be lower than states that don't use capital punishment. Nope.
States that do not use the death penalty have significantly lower murder rates.
http://www.deathpena...er-murder-rates
http://www.deathpenaltyinfo.org/files/murderratesdpvsnodp.jpg
This is not totally conclusive, you can argue correlation/causation or whatever else, but the people who really study this stuff agree:
http://www.deathpena...d-death-penalty
There's also this l
ittle theory called the "Brutalization Effect," which suggests that executions actually lead to (or at least correlate with) an
increase in crimes:
http://www.e-archive...ime_control.htm
That same article also says this about deterrence:
Finally, there is another kind of deterrence. I've been talking about general deterrence here, the idea that the notion of punishment will have a deterring effect on the general population. There is also specific deterrence, which means that when you punish someone, you deter that specific person from committing the same offense again. The death penalty is a damn effective form of specific deterrence; that person is not going to kill anyone else. But that same objective can be achieved with life in prison without parole.
So there you go. Feel free to provide an argument to show that the death penalty has any added benefit.