International demand for cotton heavily influenced domestic policies regarding slavery in the United States. European textile mills relied heavily on American cotton, which provided significant economic incentives to maintain and even expand slavery as an institution in the South. This demand prompted the US government to enact policies favorable to the expansion of cotton production and, by extension, slavery. The "gag rule" suppressing anti-slavery petitions in Congress and the Fugitive Slave Act of 1850, which compelled citizens to aid in the recovery of escaped slaves, were examples of such policies. These measures were designed to protect the interests of slaveholders and ensure the steady supply of cotton to international markets.

The Southern social hierarchy was deeply intertwined with the institution of slavery. At the apex were the large plantation owners, who wielded considerable economic and political power; their status was directly tied to the number of slaves they owned. Beneath them were smaller slaveholders, aspiring to rise in social standing by acquiring more slaves. Non-slaveholding whites, often poor and working as tenant farmers or day laborers, were nonetheless above African Americans and slaves in social standing, allowing them a sense of superiority and investment in the perpetuation of slavery. Slavery thus reinforced a rigid social hierarchy, bolstering the power and status of the white population, especially the planter elite.

Beyond cotton production, slavery permeated other aspects of the Southern economy, including tobacco, rice, and sugar cane plantations, all of which were labor-intensive crops that required a significant workforce to remain profitable. Additionally, slaves were used in various other economic activities; they worked in mining, timber cutting, in construction, on docks, and in some cases, manufacturing. Their labor underpinned the Southern economy, creating a dependency that transcended agricultural production. Slave labor was a capital investment for owners, who also traded and leased slaves for profit, further entrenching the institution within the economic fabric of the South.

The cotton gin, invented by Eli Whitney in 1793, revolutionised the cotton industry by significantly speeding up the process of separating cotton fibers from seeds. While this made cotton production vastly more efficient and profitable, it paradoxically led to an intensification of slavery. The South's landowners saw the opportunity to expand their cotton cultivation to meet the soaring demand from textile mills in Britain and the northern US. Consequently, they acquired more land and, necessarily, more slaves to work it. The cotton gin, thus, inadvertently increased the scale of slave labor required, making cotton 'king' and slavery its indispensable retainer.

Yes, there were notable differences in the conditions of enslavement between the Upper South (states like Virginia and Maryland) and the Lower South (states such as Mississippi and Louisiana). The Upper South had a more diversified economy with smaller plantations and less reliance on staple crops, which often resulted in a slightly better quality of life for slaves. They were more likely to have skilled jobs and live in closer proximity to their owners, which sometimes resulted in less harsh treatment. In contrast, the Lower South's larger plantations and greater focus on cotton and sugar cultivation often meant harsher conditions, more brutal work, and stricter control measures due to the greater number of slaves and the higher economic stakes involved.