As the old saying goes, they had a tiger by the tail. To keep making profits from slavery, they had to keep expanding or the tiger would have eaten them. Their only problem with Lincoln, was his opposition to expansion.
I try not to be judgmental of people when studying history. In my studies of the period and the disputes leading to the Civil War, I found that loyalty to the Union was of little concern for the small percentage of very wealthy people who faced the destruction of their way of life if slavery had been contained as Lincoln advocated.
They rebel leaders acted rationally (if not morally) from their economic circumstances and morals. I can rationally understand that, but sorry, I can't admire it.
I don't hate Jeff Davis, but I do 'disrespect' people today who ignorantly try to elevate him to some patriot status over some idiot notion of regional pride or perverted notion of states rights.
That is just stupid. Davis was no hero. He was just another actor on the stage.
Everybody at the time believed this, on both sides of the issue.
I'm not so sure. There was no particular reason slavery couldn't have gone on being economically profitable in the South, at least if they changed some of their farming practices that essentially mined the soil.
Plantation agriculture wasn't going to expand much into the territories anyway. Tough to grow cotton in Nebraska.
That's why for the real pro-slavery guys secession was only the first step. After breaking away from the Union, they intended to conquer Latin America and impose slavery on nations most of which had already outlawed it.
They also planned to start the African slave trade up again. Of course, the Royal and US Navies might have had some input on the practicality of that idea.