Just a historical FYI rahbert, the South was not entirely the “pro-slavery side.” The North was pro-slavery too at the time. Some of the northern states were slave states, Lincoln said the war had nothing to do with slavery, and General U.S. Grant said that if he thought the war was about freeing the slaves, he would turn in his sword and fight for the other side. Grant was also a slave owner before, during and after the war.
In contrast, General Robert E. Lee was an abolitionist. Many Southerners shared his views. President Jefferson Davis requested land owners to promise their slaves freedom in exchange for military service. The abolition movement was growing in the South before the war. The 13th Amendment that legally freed the slaves, (not the Emancipation Proclamation), was ratified by many Southern states before many Northern states.
The historical fact is that the Civil War was a conflict between TWO slave nations - the USA and the CSA. Granted, the USA had already banned slavery in some states, but the same movement was growing in some CSA states as well. Historical revisionists have spent a little over 100 years trying to paint the Civil War as some idealistic holy crusade against the injustice of slavery. That image doesn’t hold up to the historical facts. The Civil War was mainly about money, particularly taxes and resources. What the South did was no different than what the Founding Fathers did during the American Revolution. Both were acts of rebellion and armed insurrection. Both attempted to establish free and independent nations. Both were dominated by slave economies. The only difference between them is this. In the American Revolution the rebels won. In the American Civil War they didn’t.