>>509871804
The South would look a lot like an archetypical banana republic crossed with South Africa and Rhodesia. The wealthy aristocracy owning the bulk of the land and means of production, ton of number of dirt poor white subsistence farmers, and a majority non-white population of increasingly agitated slaves and free ones encouraging them (The Haitian Revolution began this way because of the loss of rights of the Mulattoes in Saint-Domingue to the Petit-blancs, which the Mulattoes saw as absurd since they contributed more to the colonial slave economy and had been there longer than them). Not a recipe for long term stability.

The economy was (and in some areas, still is) based on exportation of raw, unprocessed or barely processed materials. Cotton, tobacco, sugarcane, lumber, etc. Expect to see minimal industrialization and an economy that lacks much in the way of a middle class. It's usually cheaper for the elites to use repression versus giving concessions to the populace, so expect the rise of powerful secret police, brutal crackdowns on both slaves and as time goes on increasingly impoverished whites, and a lot of disappearances. The late 19th century anarchist and Marxist movements would absolutely terrify the aristocracy with visions of dirt poor whites and free blacks cooperating against them; I'd bet good money on something like the Paris Commune taking place in New Orleans due to the city's differing culture, attitude towards race, and lack of nearby power centers.

Probably a bloody Spartacist uprising analogue within a few decades of the war's end, and quite likely a Confederate Civil War between states trying to leave and those wanting to keep them in at some point (the CSA constitution was ironically anti-secession and restricted state's rights). Mexico, the Union, and European powers in the Caribbean would definitely be working to fuel subversive elements in the CSA, particularly if the Golden Circle conspiracy started rearing it's head.