In researching a novel I'm writing I came to the conclusion that the revolutionary war was the first civil war over slavery.
The population was pretty divided over the independence question. But then the Virginia governor Lord Dunmore's proclamation that any slave willing to fight for Britain would be emancipated turned property owners who may have been vacillating hard towards the colonial cause.
Slave holders were, of course, livid.
Jefferson's Mount Vernon nailry, in the meantime, had slave boys as young as nine years old working under the whip.
I didn't read the Jefferson article so it may have mentioned it. The Medium app makes it hard to follow links and get back to where I was.
White folks who ignore real history can't, in the long run, change it.