"Holy mass-death by giant impact, Batman!"
No, but seriously, methinks you took my POD a bit
too literally.
Hey, you asked-- and I answered.
The ONLY way the South doesn't try to buck the North and push slavery is if a charismatic enough Southern leader pushed for the dissolution of slavery in such a way as to keep the Souther aristocracy wealthy.
Sounds ASB to me, if I'm being honest.
But in case it's not, I sense a counterfactual for either the
General AH Thread or an entirely new thread all its own starting to brew here ...
Anwering this here, because it really
is an interesting point. Generally speaking, getting rid of slavery was possible with an early POD, and it was indeed a prominent Southern leader who tried to make it happen: Jefferson himself.
His attempts to dramatically curtail slavery by prohibiting its expansion beyond the states where it already existed would have doomed the institution. Since it would be dying out in the Northernmost states where it was initially legal, there would in actual fact be just six slave states. That means that
theoretically, the free states would have the two-thirds majority to call for a constitutional convention as early as the mid-1810s. In practice, it would no doubt be longer, but an amendment banning slavery (or more probably: securing that all children born thenceforth would be free by deafult) would now be an inevitability.
Everybody would grasp this long before it happened, so US slavocrats would soon be selling slaves off to the Caribbean while they still could. That would only hasten the process. Because the number of slaves would thus be lower, a negotiated "buy-out" settlement where the government pays for slaves to be manumitted becomes far more realistic.
There's never a chance for a civil war. At most, you get something like the nullification crisis. Slavery gets terminated by 1840 or so. (With the way the wind's blowing, you also don't see Nat Turner's rebellion, which hardened anti-manumission sentiment in OTL.)
The result is that there's far less of a national trauma over slavery, both because it's resolved earlier and with less fuss, and also because there's way fewer (descendants of) slaves in the USA. With earlier and more peaceful abolition, their gradual absorbtion into the populace is somewhat easier, so there will probably be less of a distinct "black" identity, and more/earlier race mixing. (Especially among the lower classes of society.)
Since there's less conflict over the right of states to keep their "peculiar institution", the South won't be going on about states' rights that much anyway, although the tendency will still exist (it derives from Jeffersonian ideals, and was in OTL merely co-opted and warped by the slavocrats). And on the other hand, without the conflict to consolidate federal power, the central government won't be able to amass so much overwhelming influence, either. (Or it'll at least take longer and be far more gradual.)
The question of "are states allowed to secede" won't be settled (with the sword), so it'll remain an open question. Without OTL's politicised traumas about the matter, the (quite valid!) Constitutional reading that it is allowed will continue to exist, albeit as an academic matter. (To elaborate: the tenth amemendment stipulates that any authority not granted to the central government by the constitution is reserved to the states or the people... and the constitution doesn't regulate secession... hence it's a matter for the states to legislate.)
That final point means that there
may eventually be a point where a state wants to secede, but it'll be much later in history, and it'll be more like Quebec wanting to secede. Or Scotland. They may well get a referendum, and they'll probably vote to stay in after all.