I think Dilorenzo and Woods downplay the morality of slavery as being the main issue of the war. Slavery was definitely an important factor. It was an important part of the Southern economy (and they had beef with the North over tariff rates) and the North was reluctant to enforce fugitive slave laws. But the North (for the most part) was not morally outraged over slavery and certainly was not going to fight a civil war over the morality of the institution.
