By 1863, the state of Union politics was deeply fractious. On the Republican side, conservative, radical and moderate Republicans largely agreed on the imperative of crushing the Confederacy, but not on the urgency — or even the wisdom — of either emancipation or arming Black soldiers and sailors. The Democrats, the opposition party, were split down the middle between “War Democrats” who supported the Lincoln administration’s military policy, though not necessarily the Emancipation Proclamation, and “Peace Democrats” (whom Republicans disparaged as “Copperheads”) who supported an immediate armistice which would effectively allow the Confederacy to leave the Union on its own terms, with slavery intact.

Particularly in the border states and throughout the Midwest, Republicans and Peace Democrats eyed each other with mounting suspicion and loathing. Republicans viewed Peace Democrats like Ohio Rep. Clement Vallandigham as traitors to the country, while Democrats bitterly opposed the Lincoln administration’s high-handed violation of civil liberties. (Lincoln had suspended the writ of habeas corpus throughout vast parts of the country, jailed newspaper editors and pro-secession state and local officials and even banished Vallandigham, who had agitated against military conscription, to the Confederacy.)

But there was more to it. For years, many Southerners and pro-slavery Northerners had pilloried the Republican Party as an organization of religious fanatics bound by a commitment to extreme and even (for the time) zany evangelical reform movements — in the words of Sen. Stephen Douglas of Illinois, “the black republican army is an allied army, composed of Know Nothings, Abolitionists, Free Soilers, Maine Liquor Law men, woman’s rights men, Anti-renters, Anti-Masons, and all the isms that have been sloughed off from all the honest parties in the country.”