Lincoln dies? Lots of things happened in 1865.
Civil War ended and by the end of the year slavery was abolished. In the South the ex-slaves were suddenly free to move about, ask for fair wages, etc, and for this, in an already devastated economy, they were often whipped in public, attacked, beaten, lynched, even burned alive and/or skinned.
You read that correctly -- SKINNED. With the carcass left hanging in public. Another era our standard history books stop short of explaining, and then leave us to uninformed conclusions. Read some of the accounts from that time; it will make your teeth curl. Once that's understood, the practice of public lynchings made into postcards with body parts sold as souvenirs, at least shows a historical connection that begins to explain it didn't just generate from nothing.
Counting from the time black people were legally citizens, i.e. not counting treatment of individual slaves which goes back way before the country was formed, that's where the "race war" started.
All of which makes my sigline all the more dumbfounding.