In April 1865 over 600,000 Americans lay dead from battle wounds and other causes directly related to their service in the armies of the Confederacy and Union during the four-year Civil War. If we adjusted the number of dead in proportion to our modern population of 300 million, it would be approximately 5,000,000 deaths—a truly gargantuan number.

There is little question about the chain of events that led to the secession of South Carolina and, eventually, eleven states total. While Southern apologists then, and...