The increased lethality of nineteenth-century “arms of precision” caused military formations to disperse in combat, transforming the ordinary soldier from a near automaton, drilled to deliver random fire under close supervision, into a moral agent who exercised a degree of choice about where, when, and how to fire his weapon. The emerging autonomy of the soldier became a central theme in contemporary tactical debates, which struggled to reconcile the desire for discipline with the individual initiative necessary on the battlefield. This tactical conundrum offers revealing insights about human aggression and mass violence. Its dark legacy was the propagation of military values into civilian society, thus paving the way for the political soldiers of the twentieth century.