What significant social effect did the Kansas Nebraska Act have on settlement in those territories?

The Kansas-Nebraska Act of 1854 promoted the idea of popular sovereignty, allowing settlers in those territories to decide whether to allow slavery. This led to a rush of pro-slavery and anti-slavery settlers moving into Kansas, culminating in violent conflicts known as "Bleeding Kansas." The act intensified sectional tensions between the North and South, contributing to the polarization of American society and foreshadowing the Civil War. Ultimately, it transformed the demographic landscape of the territories, as settlers sought to influence the outcome of slavery debates.