Of course the death penalty deters. A review of the debate.
1) Anti death penalty folks say that the burden of proof is on those who say that the death penalty deters. Untrue. It is a rational truism that all potential negative outcomes deter some - there is no exception. It is the burden of death penalty opponents to prove that the death penalty, the most severe of criminal sanctions, is the only prospect of a negative outcome that deters none. They cannot.
2) There have been 27 recent studies finding for death penalty deterrence. A few of those have been criticized. The criticism has, itself been rebutted and/or the criticism doesn't negate no. 1 or nos. 3-10.
3) No deterrence study finds that the death penalty deters none. They cannot. Anti death penalty columnists Eric Zorn of the Chicago Tribune states, "No one argues that the death penaly deters none." Yes, some do, But Zorn is correct, the issue is not "Does the death penalty deter?". It does. The only issue is to what degreee.
4) About 99% of those murderers who are subject to the death penalty do everything they can to receive a lesser sentence, in pre trial, plea bargains, trial, in appeals and in clemency/commutation proceedings. Life is preferred over death. Death is feared more than life. No surprise. Would a more rational group, those who choose not to murder, also share in that overwhelming fear of death and be deterred by the prospects of execution? Of course.
5) There are a number of known cases of individual deterrence, those potential murderers who have stated that they were prevented from committing murder because of their fear of the death penalty. Individual deterrence exists.
6) General deterrence exists because individual deterrence cannot exist without it.
7) Even the dean of anti death penalty academics, Hugo Adam Bedau, agrees that the death penalty deters .. . but he doesn't believe it deters more than a life sentence. Nos. 4-6 and 10 provide anecdotal and rational evidence that the death penalty is a greater deterrent than a life sentence. In addition, the 27 studies finding for deterrence, find that the death penalty is an enhanced deterrent over a life sentence.
8) All criminal sanctions deter. If you doubt that, what do you think would happen if we ended all criminal sanctions? No rational person has any doubt. Some would have us, irrationally, believe that the most severe sanction, execution, is the only sanction which doesn't deter.
9) If we execute and there is no deterrence, we have justly punished a murderer and have prevented that murderer from ever harming/murdering, again. If we execute and there is deterrence, we have those benefits, plus we have spared more innocent lives. If we don't execute and there is deterrence, we have spared murderers at the cost of more innocent deaths.
10) Overwhelmingly, people prefer life over death and fear death more than life.
"If we execute murderers and there is in fact no deterrent effect, we have killed a bunch of murderers. If we fail to execute murderers, and doing so would in fact have deterred other murders, we have allowed the killing of a bunch of innocent victims. I would much rather risk the former. This, to me, is not a tough call."
John McAdams - Marquette University/Department of Political Science