Never figured out how Brown could be convicted and executed for treason against the Commonwealth of Virginia when he wasn’t born there and had never lived there.
If the South had been allowed to secede peacefully, as was their constitutional right, slavery would’ve died a natural death, just as it did every where else in the West.
Chances are, the 50 states would now be decentralized into at least six different governing entities of states, and would never have gone into World War 1, which directly led to World War 2.
Not to mention that there never would’ve been an impetus to get involved in the colonial adventurism of the Middle East, with all of it’s attendant disasters.
But, you’ll never see that argument explored in federal government/NEA history books.