If you haven't read it yet, go read this story from The New Yorker.
The gist of it is that it documents a case in which Texas executed a man convicted of murder when the evidence shows not only that he was innocent, but that there was no crime committed: the fire that killed his two children was accidental.
And what is the attitude of that thug, Antonin Scalia, to the execution of an innocent man?
“This court has never held,” Justice Scalia wrote, “that the Constitution forbids the execution of a convicted defendant who had a full and fair trial but is later able to convince a habeas court that he is ‘actually’ innocent.”
So now that we have incontrovertible proof that we have executed an innocent man, who cares?