How did Kansas Nebraska act foreshadow civil war?

The Kansas-Nebraska Act of 1854 allowed settlers in those territories to decide for themselves whether to allow slavery, effectively repealing the Missouri Compromise. This led to violent conflicts known as "Bleeding Kansas," as pro-slavery and anti-slavery factions clashed over control of the new territories. The act intensified national divisions over slavery and showcased the failure of popular sovereignty, foreshadowing the larger sectional conflicts that would erupt into the Civil War. It highlighted the deepening rift between the North and South, making compromise increasingly difficult.