Although their wannabe nation was totally shattered and much of the south lay in ruins, the ex-Confederates were quickly pardoned for their actions and their attempt to break up the country.
Slavery was reinstated in anything but name, and blacks were second rate citizens, without the south having to deal with the stigma of slavery. Through all kinds of laws and shady dealings, white men, especially rich white men, could get the labor of black people real cheap.
Although history is usually written by the victor, this wasn’t really the case here. The militarily completely vanquished Confederacy won the war by dominating the narrative afterwards.
‘The lost cause’ mythology became widely accepted, practically all over the world. It’s the story of the brave and superbly led Confederates who only lost because the darn yankees totally outnumbered them, and certainly not through any Confederate blunders ( of which there were many).
To this day many people believe the war was fought over ‘state rights’ or ‘tariffs’, not to ensure slavery could expand into new territories.
I myself grew up with books that praised the Confederacy for their Spartan like efforts to almost defeat the giant Union, which was only fighting to exploit the south and for no other reason.
Today this defeated Confederacy has a president in the White House that voices everything that the Confederacy stood for, individualism, the dominance of rich people, racism, repression, vicious social restriction, white pride and arrogance, isolationism, a disdain for intellectuals and culture, and an adoration of violent sort of masculinity and war.
The Confederacy lost on the battlefield, but they certainly won anywhere else.