“Beware the people weeping /
When they bare the iron hand”
—Herman Melville, “The Martyr”
It is one of the most famous photographs of the nineteenth century: Alexander Gardner’s picture of four hooded figures dangling from a gallows in the old federal penitentiary in Washington, D.C. on July 7, 1865. On that sweltering afternoon, about a hundred civilians mingled in the courtyard below, while soldiers patrolled the walkway on top of the brick wall behind the gallows. Throughout this spectacle, the crowd chanted, “Remember Booth the murderer.” John Wilkes Booth, however, was not present, having been shot to death in a Maryland barn by a Union soldier less than three months earlier. The four persons hanged had been convicted of conspiring with Booth in his assassination of President Abraham Lincoln. Three of the four—George Atzerodt, David Herold, and Lewis Payne—were lowlifes who had indeed been privy to Booth’s plot. The fourth, Mrs. Mary Surratt, was almost certainly a scapegoat sacrificed to the bloodlust of a grieving nation. How these four prisoners came to their fate (deserved or not) is a cautionary tale for our time.
The murder of Lincoln at Ford’s Theater on the evening of April 14, 1865, only five days after...