There are some crimes, the death penalty advocate contended, that are so heinous that society must express its outrage by imposing the ultimate punishment – death. The death penalty, he claimed, was a deterrent to violent crime. For society not to use it is to bear responsibility for the deaths that follow when murderers go undeterred.
Responding, the opposing attorney asked rhetorically, “Why is death the ultimate punishment? What if I could demonstrate to you that torture is an even better deterrent to violent crime? Would we then say, ‘Then for every murderer you do not torture, you are taking an innocent life?’ What about killing the wives and children of murderers? They used to do things like that in biblical times. What if I could demonstrate to you that killing the wives and children of murderers was an even better deterrent?”
The point, he said, is that we have standards of behavior as a civilized society. We set limits beyond which we as civilized people do not go. Government should be constrained by the same standards of behavior, and ought not be allowed, under color of law, to practice the same behavior it punishes.
Much of the torture debate is an argument over efficacy, over whether or not torture "works." As with the death penalty argument above, efficacy is beside the point. Torture is another standard civilized societies do not violate. Torture is a crime. Torture is against the law. Period.