Naturally, the winners of history get to decide what their legacy is.
It is why the Allies weren't put before war crimes tribunal for firebombing Japan.
Total war.
In contrast to the Nazis and Imperialist Japan, the Confederates were gentlemen. The problem with the Confederacy was that the most fanatical supporters of slavery believed their own PR -- that slavery was a boon to the slaves. Slavery was doomed in the United States because the British model of emancipation was well suited to the United States.
We will never know what Lincoln was planning. The British solution meant that there would never be any slave revolts. Freedmen and their descendants would never become a fifth column who would serve anyone who would promise their emancipation.
Slaves commonly abandoned the plantations as the Union front came nigh. With such came the economic collapse of the Confederacy -- basically one plantation at a time. The Confederacy slowly starved.
Maybe -- but the planters still dominated the political order in those states.
