If I didn’t manage to convince you of the stupidity of deterrent talk in my two previous posts (here and here), then neither will I manage today. Still, I’m a hopeless optimist by nature, so I’ll try anyway. A vital presupposition in the deterrence argument in favor of capital punishment (or any type of punishment by the way) is the minimally rational nature of criminals: if criminals don’t weigh the costs and benefits of actions before they undertake them, an extra cost as heavy as death won’t make any difference to their actions. And they don’t:
The tenet that harsher penalties could substantially reduce crime rates rests on the assumption that currently active criminals weigh the costs and benefits of their contemplated acts. Existing and proposed crime strategies exhibit this belief, as does a large and growing segment of the crime literature. This study examines the premise that criminals make informed and calculated decisions. The findings suggest that 76% of active criminals and 89% of the most violent criminals either perceive no risk of apprehension or are incognizant of the likely punishments for their crimes. (source)
It seems that criminals, like the rest of us, are seldom the cold, mechanical and calculating types. And the best thing about this: even if it was all wrong and capital punishment could deter, it would still be unacceptable for other reasons.