This is probably one of the first times that we've significantly disagreed
And yes - perhaps my 'all or nothing' viewpoint merits being called unreasonable - I'll take that. But I remain convinced that taking the life of any individual (be it a good life, or a 'threat' to society - by whoever's standards) is apprehensable.
Where I was going with my previous post, is that once you deem it within the scope of the law to 'legalize' murder - state sactioned at that - it leads to a slippery slope. Laws are made by people, and people are prone to errors in judgement. Let's not put the right to kill in 'ordinary people's hands. As you said the line is not solid. Criminal X may be sentenced to death while Criminal Y get's to live - and the crimes may be quite similar; it will depend on WHO does the judging. That too is incorrect.
Finally, you've shot down your own "save our resources" argument. Every death sentence will be accompanied by appeals, more appeals and sumpreme court decisions. Everyone of these guys will deny his crime. Courts are costly - and before you know it, you've spent more money defending your prosecution case/sentencing, than you have if he'd been put away for life. Here in Canada (in the last few years) I know of at least three cases where a criminal convicted of murder, serving a life sentence hsa been exonerated due to new evidence - Marshall served 18 years in prison before being declared not-guilty. Have if we had fried the guy? Who pays for that?