Wilkerson uses the term “caste system” throughout The Warmth of Other Suns to refer to a rigid social structure that allows no intermixing between social classes and offers no upward mobility. The South was truly a caste system—the complete opposite of the America’s founding principles. In the North, although there was prejudice, there were also more options, and the social structure was different.

The South was a feudal society, with a small landholding aristocracy subjugating enslaved people  who worked the land. This fixed social order and its strong class distinctions upended during the Civil War and after the end of slavery. Following the Reconstruction period, white Southerners enacted laws and regulations that would re-establish the previous way of life, which brought back near-slavery conditions. The small hope that freed African-Americans could unite politically with poor whites was dashed by policies enforcing Black inferiority and stoking poor white resentment about people with whom they now competed for jobs. Whatever rights the African-American community had gained after the Civil War were stripped away without legal recourse. Instead, whites dealt swiftly and violently with African-Americans aspiring to move out of the bottom caste.