For some, slavery was an issue. If you would have asked a typical Union soldier he was fighting to free the slaves, he would of said, Hell no! You would have gotten the similar answer from the typical Confederate soldier if he were asked, Are you fighting to own slaves? The attempt to pain the Union as an army on a moral and spiritual mission is pure fantasy. The reason for going to war was to “save” the Union. Only about 5% of whites owned slaves in the South. The other 95% never owned a slave and lived in worse economic conditions than many slaves. They had no vested interest in slavery, but they wanted to keep their Southern culture.
When I was growing up my mother didn't drive. We had one car and it was titled in my father's name. You could truthfully say that only 20 percent of the family owned a car. But 100% got benefit from that car ownership. The same is true with slave ownership. It may be true that only 5% of all Southerners owned slaves. But if all of them were married then suddenly 10% of all Southerners derive benefit from that slave ownership. Add a couple of kids and the percentage goes up. The more accurate comparison would be to look at the number of slave owners and the compare it with the number of families listed in the 1860 census. Look at that and you see that in states like Mississippi half of all families owned slaves. In the confederacy as a whole between one-third and one-quarter of all families had slaves. Look at it in those terms and it's easy to see why they would fight for it.
...and lived in worse economic conditions than many slaves.
Nonsense.
They had no vested interest in slavery, but they wanted to keep their Southern culture
A culture built on slavery.