Matters of life and death

I heard an interview with someone who'd been campaigning against the death penalty: she brought out her trump card, that a large fraction of those condemned to death are later freed on appeal. I used to follow this line too: obviously if someone's been executed it's a bit late to find out they're innocent. But I'm not sure this argument holds: for while you cannot bring someone back to life, neither can you restore the health, liberty and freedom lost to someone under a long sentence, even if they are released eventually. The case for having a judicial system that doesn't make mistakes is a strong one: the precise nature of the punishments an ineffective one misapplies is not really relevant. I know there are subsidiary arguments: that juries will be wary of finding someone guilty if they know they are sentencing them to death. But then they damn well should be - that's the whole point of 'beyond reasonable doubt'. For me, the clinching argument has to be the paradox that those who argue for the sanctity of human life (in terms of murder victims) are those who wish the state to ignore such sanctity. This reminds me of the animal rights extremist who ended up justifying terrorist attacks on animal laboratories "I must do something to stop this animal holocaust, and if some people get killed in the process, well, the end justifies the means", when of course their objection in the first place was that no end could justify the application of immoral means.