Cause. Singular. Not plural. We talk about the cause of the American Civil War because there was one overwhelming cause -- slavery. Not tariff disputes. Not states' rights. The Civil War was fought over the preservation of slavery in the south and its expansion to the west. But, perhaps no other aspect of the history of the United States has been so distorted and mythologized as the causes of the Civil War. Professor Philip Nash joins us to explain why slavery was such a dominant issue from the founding of the United States until 1865.