I have mentioned that I am listening to the history of US Presidential Elections, all 58 of them, entitled "Wicked Game." I just finished listening to 1860, relieved to finally hit one where I knew much (though not all) of the relevant information. Since 1828 it has been a tough slog, filled with names I did not know and important bits I had gforgotten, or never knew.
They are about 40 minutes apiece, but the election of 1836 came in at 60+ minutes. At the end, I still couldn't tell what had happened. History is messy, and our shorthand versions are usually somewhat misleading. But I will say that slavery dominated the discussion of every election throughout the first half of the 19th C. The statement I read recently holds true: You first learn that the Civil War was about slavery. Then, as you get some education, you learn that it was about the Port of New Orleans, and tariffs, and states' rights, preserving the union from exterior pressures and attack, immigration, and agricultural versus manufacturing interests and a dozen other things. Then, when you have learned a great deal more, you find that it was about slavery after all. That, and the natural inclination everyone feels to defend their territory from rule by outsiders (even if they are completely wrong). I think that is about true.