In antebellum Alabama, wealthy planters created large cotton plantations based in the fertile central Black Belt of the upland region, which depended on the labor of enslaved Africans. Tens of thousands of slaves were transported to and sold in the state by slave traders who purchased them in the Upper South. In the mountains and foothills, poorer whites practiced subsistence farming. By 1860 blacks (nearly all slaves) comprised 45 percent of the state's 964,201 people. Tensions related to slavery divided many state delegations in Congress, as this body tried to determine the futures of territories beyond the Mississippi River. Following the Congressional passage of the Compromise of 1850, which assigned certain territories as slave or free, in Alabama people began to realign politically. The States' Rights faction, joined by many Democrats, founded the Southern Rights Party, which demanded the repeal of the Compromise, advocated resistance to future encroachments, and prepared for secession. The Whigs were joined by the remaining Democrats and called themselves the "Unionists". The party unwillingly accepted the Compromise and denied that the Constitution provided for secession. Since the turn of the 19th century, development of large cotton plantations had taken place across the upland Black Belt after the invention of the cotton gin made short-staple cotton profitable. Cotton had added dramatically to the state's wealth. The owners' wealth depended on the labor of hundreds of thousands of enslaved African Americans, many initially transported in the domestic trade from the Upper South, which resulted in one million workers being relocated to the South. In other parts of the state, the soil supported only subsistence farming. Most of the yeoman farmers owned few or no slaves. By 1860 the investment and profits in cotton production resulted in planters holding 435,000 enslaved African Americans, who made up 45% of the state's population. At the time of statehood, the early Alabama settlers adopted universal white suffrage. They were noted for a spirit of frontier democracy and egalitarianism, but this declined after the slave society developed. J. Mills Thornton argues that Whigs worked for positive state action to benefit society as a whole, while the Democrats feared any increase of power in government or in state-sponsored institutions as central banks. Fierce political battles raged in Alabama on issues ranging from banking to the removal of the Creek Indians. Thornton suggested the overarching issue in the state was how to protect liberty and