I have another blog post queued up, but with today's events this "idea" is worth reiterating: end the death penalty.
I have no interest in, nor patience with, moralistic arguments about the death penalty. If we lived in a world in which you could know something with 100% certainty, then those arguments would be useful. But we don't. Every single source of evidence used in the judicial system has an error rate. Some sources (such as witness testimony) have alarmingly high error rates. There's no combination of error rates that, when compounded, yield 100% certainty.
The death penalty might be worth debating if we lived in a world of absolute certainty. We don't. Not even remotely close, in fact. Keeping an innocent person in jail isn't a great solution either but at least the possibility for some kind of restitution exists in the (again, remarkably likely) event that the evidence is flawed.
Update: The governor stayed the execution at the last moment.
Update 2: Looks like even DNA evidence can have high error rates.