This rare 1862 photograph shows slaves escaping to Federal lines in Virginia. Even before the Emancipation Proclamation, the advance of Union armies led to the de facto abolition of slavery, as African Americans fled to the safety of Federal lines. But things were far different in Missouri. Though troops from Kansas began to liberate slaves at the outset of the conflict, the bulk of the Union war effort was carried on by loyal Missourians, organized into a variety of militia forces. Many of these troops, and their commanders in particular, were conservative former Whigs, and many were slaveholders themselves. Initially, at least, most saw no conflict between their Unionism and their continued acceptance of slavery. In Clay County, the local militia commander was Colonel James H. Moss, who deployed his men to catch and punish escaping slaves.

As the war progressed, however, a Radical faction of Unionists emerged. Determined to do whatever it took to suppress the rebellion, the Radicals came to embrace emancipation. The creation of the Provisional Enrolled Missouri Militia in 1863 sped up the radicalization of the state's military forces, which increasingly offered protection to escaping slaves. Just prior to the Lawrence massacre, a neighbor of Jesse James's family recorded a well-organized mass exodus that conjures up an image much like the one shown here. "They left on the night of the 13th of August, taking 6 horses, and a quantity of stolen clothes," Kate Watkins wrote. "There was a general stampede the night they left. There is very few negroes left in the country." Most of Jesse's mother's slaves took their freedom before the end of the war, though Charlotte, a longtime personal servant to Zerelda Samuel, remained with the family for her entire life. The distintegration of slavery enraged Unionists such as Col. Moss, and led to a lasting three-way political split between Radicals, Conservatives, and Confederates.