Recall the story about the explorer who encounters an aboriginal tribe for the first time. “Are there cannibals among you?” he asks. “No,” they reply, “We ate the last one yesterday.”
To constitute a civilized community by eating the last cannibal, the final act must be called something else. It is a kind of original sin that must be erased from memory.
Similarly, the transition to a modern legal order in the American “Wild West” was accomplished through brutal crimes and the creation of myths to cover them up. As a character in the John Ford western "The Man Who Shot Liberty Valance" put it, “When the legend becomes fact, print the legend.”