Question

How did the whole issue of slavery eventually lead to the civil war?

Answer 1

Technically it didn´t, that was dubbed the reason because the south had broken away from the north. They were arguing over aspects of the Constitution and slavery was one of them

Answer 2

The South was for slavery because their agricultural industry required intensive labor, but the North thought slavery was plain wrong and were horrified at the conditions slaves were in, and how they were treated.

I hope I helped :)