An unerring fire

On 12 April 1864 a Confederate cavalry force, led by General Nathan Bedford Forrest, assaulted and captured an incompetently defended Union fortification in western Tennessee, near Memphis. The unusual number of predominantly African-American troops who were killed during the subsequent rout led the Northern public to charge that a racist massacre had occurred. Although Lincoln's cabinet decided against systematic reprisals, outraged Federal soldiers took vengeance during several small engagements, foraging expeditions, and anti-guerrilla campaigns. For its part, the Confederacy defended the…