Agreed, I don’t see how anyone could read any of the letters of secession and not instantly see how slavery is the primary reason. South Carolina’s letter (first state to leave) is a nice easy counter argument to the states’ rights crowd, since it goes on and on for pages explicitly denying the northern states rights and whining that the north should be forced to enforce slavery laws there by the federal government, and how dare the northern states disobey federal laws enforcing slave owners “rights.”