In this video segment, from the PBS documentay Looking for Lincoln, host Henry Louis Gates, Jr. reflects on the unprecedented scale of the Civil War, wondering how so many soldiers on both sides could have marched so enthusiastically to their deaths. Gates' interview with historian Allen Guelzo explores both the specific horrors of the battle of Gettysburg and President Lincoln's personal contempt for the Confederate States of America, which he refused to officially recognize as anything more than an insurgency.