If you look at the newspapers of the time and the different acts passed by Congress, it is pretty clear that the northern manufacturing companies controlled Congress. They passed acts and tariffs that were in their best interests and economically punished the agricultural south.
Then the slavery factor lent a veneer of moral superiority. It was okay to dislike/distrust/abuse the south...they enslaved human beings! Forget the fact that less than 3% of the population owned slaves...the south was evil!
You can only poke the bear so many times until you get some claws and teeth. Economically abused and disparaged, the south wanted autonomy. The north did not have the best interests of the farmers in the south at heart.
Mom’s side of the family is mostly from the south...related to the Lees of Virginia. Dad’s side of the family is mostly from the north with ties to the Buchannans. Funny, we never had any get togethers with BOTH sides of the family...
Don’t know why. Buchanan and Lee pretty much were on the same side even though Buchanan was from Pennsylvania.