"the same is true of slavery, it can be said, truthfully, that Slavery really had nothing to do with the War, and yet at the same time, we all know it had everything to do with the war."

I respectfully disagree with that statement. I have yet to find one single source that can actually support the statement that the cause of the war was slavery. However I have found plenty to show that the cause of the war was the "collection of revenue."