Final answer:
Southern society before the Civil War was dominated by a white planter elite that held considerable power and maintained a social structure based on slavery and white supremacy.
Step-by-step explanation:
Before the Civil War, southern society was dominated by a white planter elite, which comprised an aristocratic gentry in the Upper South and wealthy cotton growers in the Deep South. This planter elite wielded considerable economic and political power and shaped much of the region's culture and policy to protect and expand the institution of slavery. The social hierarchy was steeped in notions of white supremacy, with white men, especially the wealthy planters, asserting authority as patriarchs within their families and communities while enslaved Africans and African Americans performed forced labor, and white women adhered to prescribed domestic roles.