Half the country seceded from the other half when Abraham Lincoln was elected because half the country couldn't abide his position on slavery. You would think 150 years later this had all become pretty historically incontestable. Yet millions continue to contest it in the face of history. Rather the denial of slavery and all its monstrous repercussions defines to one twin America what the country is and means, and therein is the DNA of those "alternative facts" that people believe when they can't stand to believe the truth.