Taxes and slavery.
The main reason for the Civil War in the United States was a dispute between the north and south states over the Slavery issue, the southern states had the vast majority of their economy depending on the slaves to work and make them richer, and wanted to keep it that way, while the northern states believed on a more fair and equal world for everyone and wanted to abolish slavery, they also wanted a more powerfull federal government with the possibility to raise bigger greater taxes, contrary to what the southern states wanted on a more governor-state centered politics and taxes raising. Hope this helped!