“Five years later, 750,000 Americans were dead. But the fact that such carnage had been wreaked for a cause that Ulysses S. Grant called “one of the worst for which a people ever fought, and one for which there was the least excuse” invited the damnation of history. Honor is salvageable from a military defeat; much less so from an ideological defeat, and especially one so duly earned in defense of slavery in a country premised on liberty.”