There won't be a "Civil War" in TTL, as the rump USA would either put up w/slavery until it runs its course in the late 19th/early 20th century or just split up, like marriages sometimes do.
Why so? I'm happy to hear anything you have to say, but I don't understand why.
Really hard to say; abolitionism was not simply a political and social movement in New England, any more politics centered around slavery to the knife and white supremacy/mastery was limited to the Deep South.
OK. That was part of the thought: that abolitionism and free-soil ideas would still be presented in the rump North but would be considerably weaker without New England, so the balance of power between slave states and free states would be changed but not set firmly in favour of one side. The other part was the precedent set by a successful secession from the United States.
Without the feeling of threat, then, (please forgive me if I've misunderstood you) are you saying that Southern slave-owners (outside the Deep South, that is) would be less militant about slavery—more like 1810 than 1860—than IOTL?
And given the above, and the reality that New England had a tremendous economic and political interest in keeping the nation together after 1787, I just don't see anything akin to an independent New England occurring. I think you would have needed a departure point during the Revolutionary era, and even that is difficult - "we all must hang together or we will hang separately" was true.
Best,
The idea was that with different US leadership the crisis over the US embargo on British goods goes south, which (in addition to New Englander discontent over what is considered in New England as an overly powerful federal government dominated by the Virginian dynasty, plus British support of the Republic of New England and, of course, a healthy dose of luck) leads to an independent New England
because of New England's economic interests.
White Suprecism was not just the South. Not even close. Lincoln himself wanted colonize the African population in Central America or somewhere else, and was an extreme white supremecist. The North is just as racist as the South is, only they dont own slaves, and thats because there is really no point, the north is mostly industry and the immigrants took up most factory and labor intense situations. The North aint a Haven, your just as liable to be lynched in Boston as you are in New Orleans.
White supremacism existed in the North, yes, but Lincoln was, whatever else might be said about him, firmly anti-slavery on ideological grounds, and his view wasn't immensely unusual in the North.