1.The Fight between Abolitionists (North) and Slave States (South).
As the North became more industrialized because of poor
lands and the South was the other way around, the slaves
were many more in the South, where they lived of
agriculture (mainly cotton plantation) and therefore
depended on slaves.
The Northern States wanted to abolish slavery and give
black men human rights. In the other hand the Southern
States were pro-slavery because, as said before, they
needed slaves to work on their plantations.