Whitneys cotton gin made cotton production enormously profitable, and created an ever-increasing demand for slave labor. The Souths dependence on cotton production tied it economically to the plantation system and racially to white supremacy. The cultural gentility and political domination of the relatively small plantation aristocracy concealed slaverys great social and economic costs for whites as well as blacks.

Most slaves were held by a few large planters. But most slaveowners had few slaves, and most southern whites had no slaves at all. Nevertheless, except for a few mountain whites, the majority of southern whites strongly supported slavery and racial supremacy because they cherished the hope of becoming slaveowners themselves, and because white racial identity gave them a sense of superiority to the blacks.

The treatment of the economically valuable slaves varied considerably. Within the bounds of the cruel system, slaves yearned for freedom and struggled to maintain their humanity, including family life.

The older black colonization movement was largely replaced in the 1830s by a radical Garrisonian abolitionism demanding an immediate end to slavery. Abolitionism and the Nat Turner rebellion caused a strong backlash in the South, which increasingly defended slavery as a positive good and turned its back on many of the liberal political and social ideas gaining strength in the North.

Most northerners were hostile to radical abolitionism, and respected the Constitutions evident protection of slavery where it existed. But many also gradually came to see the South as a land of oppression, and any attempt to extend slavery as a threat to free society.