Slaves actually called slaves where relatively uncommon in history. Include peasant uprisings and several more become relevant. However, the important bit for US isn’t the long term results it’s the chaos involved in these civil wars.

The Third Servile War for example grew from 70 slave-gladiators to ~120,000 men in 2 years and won several significant battles vs the Roman Army. You really don’t want to see the modern version of that kind of fighting. https://en.wikipedia.org/wiki/Third_Servile_War