I've got a theory here. One that I'm pretty sure you won't spill the beans on yet if it's true, but I'll say it regardless.
Given this is referred to as the Second full-on American Civil War and we haven't heard from the Confederation yet, I don't think they'll secede. I think Northern states will try and join the Confederation, who's attitude on the states would allow them to do what they please regarding slavery.
Except there is a wikibox further up the thread which suggests that the Confederation is also going to split.
Greetings! This timeline is the spiritual successor to A Shining Valley, which you may have seen posted on the forum before. As it was my first timeline, it was messy and crude as it experience significant revision over the months, which honestly ruined the narrative in many ways. For the past...