I asked Michael Burlingame, author of the definitive two-volume 2024-page biography, "Abraham Lincoln: A Life," what would have happened if Lincoln had lived. Some cynics have suggested that Lincoln would not have been made into a secular saint, that indeed he might have been impeached just as his successor Andrew Johnson was, in the bitter debate over how to manage Reconstruction. But Lincoln was a much better politician than Johnson was, Burlingame said. It's possible that a kindler, gentler implementation of Reconstruction by Lincoln might have led to a civil rights movement in the 19th century akin to what happened nearly 100 years later with the 20th century civil rights movement. So, one can argue that Abraham Lincoln's assassination set the nation back nearly 100 years.