This doesn't speak too well for the death penalty, in my opinion. With all the attention and care that must have gone into this high-profile (and pretty clear cut) case, plus McVeigh sitting in prison for years now, and they discover just days before the execution that the government screwed up again?
What do you think happens when the accused is some anonymous "driving while black" type or some local white trash that nobody cares about? I bet they make bigger mistakes and find out later, huh?
I strongly support the right of law enforcement and ordinary citizens alike to use deadly force in extreme emergency situations, but can't see how you and me together (i.e. society) got any more right to sit back and methodically kill someone than what you and me separately would have. Zero plus zero is still zero.