>>17919881 (OP)
There was a global depression in 1819. Industrialists petitioned the federal government to create tariffs so that it would be too costly for the southern states to trade with anyone other than the northern states.
The reason for this is that these industrialists needed raw materials to create furniture, perfumes etc and the south was largely agrarian. Their only other major trading partner was Britain. The northern states had highly sought-after timber and fish, but everything else required imports of cotton, iron etc.
These tariffs were bad for a few reasons. The first was that it ruined many sectors of the southern economy. The second was that the federal government said these tariffs would only last a few years, but they lasted until the mid 1800's, ranging from 18% to 50%.
Lincoln coming into politics was a big deal because he was making overtures to ending slavery forever, which is what fueled what remained of the southern economy. Industrialization never really took off in the south because the ambient humidity, which often reached 100%, coupled with the heat often killed people. Working inside of an enclosed building in the deep south during the height of summer was a death sentence, which is where slaves came into the picture.
Lincoln himself said he didn't want to end slavery if it meant keeping the union together, but then he literally threatened to destroy the southern states during his inauguration speech, which only heightened tensions even more.