I’m going to pull the lens back a little bit and note the near-congruence of Lincoln’s passing with the 70th Anniversary of Franklin Roosevelt’s death on April 12, 1945. Death of a President in office, whether by assassination (Lincoln, Garfield, McKinley, JFK) or natural causes (W. Harrison, Taylor, Harding, FDR) is a trauma for the nation that sticks forever in the memory of the contemporary generation. As an example, people who have a memory of 1963 can tell you where they were when JFK was assassinated.
The timing and manner of Lincoln’s assassination, coupled with the fact he was the first President to die violently in office, was a significant trauma and national tragedy on top of the war that was just ending. The reaction to his death in the Union and what was left of the Confederacy (especially as expressed by Johnston and Breckinridge to Sherman) illustrates the profound impact of the event.