Why did the eleven southern states leave the union in 1860-1861?

The eleven southern states seceded from the Union between 1860 and 1861 primarily due to tensions over slavery and states' rights. The election of Abraham Lincoln, who was perceived as anti-slavery, heightened fears among Southern leaders that their way of life and economic interests would be threatened. Additionally, many in the South believed that they had the right to determine their own laws and governance, leading them to pursue secession as a means of preserving their social and economic systems. This ultimately culminated in the outbreak of the Civil War.