# Bleeding Kansas Period of violent confrontation (1854–1861) in Kansas Territory between pro-slavery and free-state settlers following the [[Kansas-Nebraska Act]]'s introduction of popular sovereignty on the slavery question. The guerrilla warfare — including the Pottawatomie massacre by John Brown and the sacking of Lawrence — killed over 50 people and made Kansas a national proxy war over slavery's expansion. Bleeding Kansas demonstrated that the slavery debate could not be resolved through democratic compromise, presaging the [[American Civil War]] and illustrating how [[White Supremacy]] was defended through organized violence long before the formal Confederate rebellion.