The motivations of the supporters of the Union and the Confederacy, respectively, were not uniform; some Northern soldiers were indifferent on the subject of slavery, but a general pattern can be established. As the war dragged on, more Unionists came to support slavery's abolition, either to cripple the Confederacy or on moral grounds. Confederate soldiers fought to protect a Southern society of which slavery was an integral part. Opponents of slavery considered it an anachronistic evil incompatible with republicanism. The strategy of the anti-slavery forces was containment—to stop the expansion of slavery and thereby put it on a path to extinction. The slaveholding interests in the South denounced this as infringing upon their constitutional rights. With large parts of the Southern population in slavery, white Southerners believed the emancipation of slaves would destroy Southern families, society, and the South's economy, with large amounts of capital invested in slaves and longstanding fears of a free black population. Many Southerners feared a repeat of the 1804 Haitian massacre, when former slaves murdered most of Haiti's white population after the successful slave revolution. Historian Thomas Fleming points to the historical phrase "a disease in the public mind" used by critics of this idea and proposes it contributed to the segregation in the Jim Crow era following emancipation. These fears were exacerbated by the 1859 attempt by John Brown to instigate an armed slave rebellion in the South.