BY THE EARLY NINETEENTH CENTURY, northern states had either abolished slavery or put it on the road to extinction, while southern states were building the largest slave society in the New World. Regional differences increased over time, not merely because the South became more and more dominated by slavery, but also because developments in the North rapidly propelled it in a very different direction.

By 1860, one-third of the South’s population was enslaved. Bondage saddled blacks with enormous physical and spiritual burdens: hard labor, harsh treatment, broken families, and, most important, the denial of freedom itself. Although degraded and exploited, they were not defeated. Out of African memories and New World realities, blacks created a life-affirming African American culture that sustained and strengthened them. Their families, religion, and community provided defenses against white racism and power. Defined as property, they refused to be reduced to things. Perceived as inferior beings, they rejected the notion that they were natural slaves.

The South was not merely a society with slaves; it had become a slave society. Slavery shaped the region’s economy, culture, social structure, and politics. Whites south of the Mason-Dixon line believed that racial slavery was necessary and just. By making all blacks a pariah class, all whites gained a measure of equality and harmony.

Many features of southern life helped to confine class tensions among whites: the wide availability of land, rapid economic mobility, the democratic nature of political life, the patriarchal power among all white men, and, most of all, slavery and white supremacy. All stress along class lines did not disappear, however, and anxious slaveholders continued to worry that yeomen would defect from the proslavery consensus. But during the 1850s, white Southerners’ nearly universal acceptance of slavery would increasingly unite them in political opposition to their northern neighbors.