There's the old joke - never say "oops" in the operating room. Of course, where you really must never say "oops" is in the execution chamber. There is hard evidence that America has unjustly killed 25 people in this century alone.

A Dutch lawyer is now working in the US to stop the executions of as many people as he can. The warden of the prison where he works says that he supports the work of this man because it helps to make sure that they do not execute an innocent prisoner. Of course, you can never really be sure about anything, so as long as you execute people you have to accept the fact that you are going to kill the wrong person every so often.

My own view is that the simple fact of the certainty of occasional error is itself a sufficient reason to end the death penalty. What does it feel like to go to your death knowing that you are innocent of the crime for which you have been convicted?