The issue of slavery was the primary cause of the Civil War. The Southern states were heavily dependent on slave labor to work their plantations, while the Northern states were increasingly opposed to the institution of slavery. As tensions between the North and South grew, the issue of slavery became increasingly divisive, eventually leading to the outbreak of war.
2. States' rights
The question of states' rights was also a major factor in the Civil War. The Southern states believed that they had the right to secede from the Union if they felt that their interests were not being represented. The Northern states, on the other hand, believed that the Union was indivisible and that no state had the right to secede. This conflict over states' rights was a major contributing factor to the outbreak of war.