The fact that slavery existed came to dominate the economy, the politics, and the society of the South. It caused the South to become very different from the North in significant ways. These helped to cause the Civil War. Let us look at the most important impact of slavery in each of these categories.
Economically, slavery helped to ensure that the economy of the South would remain agrarian and would not progress as much as it might otherwise have. The South’s capital was largely tied up in slaves. This made it very hard for Southerners to have the kind of money that would have been needed to invest in other kinds of economic ventures. Moreover, labor-saving machinery was not something that was useful to the South. It would simply have made their slaves redundant, and they would have had a hard time getting any money for them. Thus, slavery caused the South’s economy to remain somewhat stagnant.
Socially, slavery is said to have helped keep the South together. There were massive differences in wealth in the South, but slavery helped poor whites to identify with the rich whites. It helped them to feel that they were all white and were all superior to the African Americans. That helped the whites feel more solidarity with one another.
Politically, slavery helped make the South more aristocratic. Only a few families could afford the huge plantations that made the most money. This gave these families a great deal of political power. This was very different from the conditions in the more egalitarian North.
Thus, slavery had a significant impact on many aspects of life in the South.