The Civil War was about deciding who counted as one of us, and what rights, privileges, and duties we would afford each other. It was not a forgone conclusion that America would denounce slavery as unconditionally wrong. Asa Mahan was an abolitionist, college president, author, and clergyperson who advocated that there is intrinsic value in every human being, and for our country to honor its covenant with its citizens, all must actively engage...