The South WAS pro-Union. They recognized the benefits of a shared defense. Free trade. Strength in numbers. Hence the forming of the Union in the first place. They simply didn't think the benefits were worth the growing Federal intervention in what they believed were their constitutional rights as states.

This argument has always struck me as rather absurd. Either the life of the unborn child has human rights or it doesn't. Why would the circumstances of the conception have any influence on the value of the conceived?