"The Civil War caused in part by Chief Justice Taney's dictum in the Dred Scott case that Congress could not bar slavery from the territories, resulted, of course, in the destruction of slavery. The Thirteenth Amendment formally abolished the institution. The Fourteenth and Fifteenth Amendments, which the Southern states were forced to ratify in order to get back into the Union, made Blacks citizens, prohibited the states from depriving "all persons" of life, liberty, or property, without due process of law, and made it illegal to deny anyone the right to vote "on account of race, color, or previous condition of servitude." - Quarrels That Have Shaped the Constitution. 2nd ed
It's my old ConLaw text I just happened to be re-re-reading.
I suggest your Con-Law text author(s) need to reread Texas v. White.