If we execute murderers and there is in fact no deterrent effect, we have killed a bunch of murderers. If we fail to execute murderers, and doing so would in fact have deterred other murders, we have allowed the killing of a bunch of innocent victims. I would much rather risk the former. This, to me, is not a tough call.
I never saw daffodils so beautiful. They grew among the mossy stones about and above them; some rested their heads upon these stones, as on a pillow, for weariness.