When I saw the head part from the body, and each of them fall separately into a box with a thud, I understood–not in my mind, but with my whole being–that no rational doctrine of progress could justify that act, and that if every man now living in the world, and every man who had lived since the beginning of time, were to maintain, in the name of some theory or other, that this execution was indispensable, I should still know it was not indispensable: that it was wrong.

Leo Tolstoy–Leo Tolstoy, upon returning from France in 1857

Blood can not restore blood.

–Abraham Lincoln, after the Fort Pillow Massacre, when surrendering soldiers were slaughtered in cold blood