From the book:
The twenty-day death pageant transfigured Abraham Lincoln from man to myth. On the day he was murdered, he was not universally loved - even in the North. His traveling corpse became a touchstone that offered catharsis for all the pain the American people had suffered and stored up over four bloody years of civil war. For whom did they mourn? For their slain president, of course. But the outpouring of national sorrow could not be for just one man. "Not for you, for one alone;/Blossoms and branches green to coffins all I bring," wrote Walt Whitman. And so they mourned, not for this one man alone but for all of the men; for every son, every brother, every lover, and every husband, and every father lost in that war. It was a though, on that train, in that coffin, they were all coming home. Lincoln's death pageant for Abraham Lincoln was a glorious farewell to him and to the three hundred and sixty thousand men of the Union who, like their Father Abraham, had perished for cause and country.