What did the Kansas-Nebraska Act of 1854 allow?

The Kansas-Nebraska Act of 1854 is significant in American history because it introduced the concept of popular sovereignty, which allowed the settlers of a territory to determine whether slavery would be permitted within their boundaries. Specifically, residents of the Kansas and Nebraska territories were given the power to decide for themselves if they would allow slavery, essentially nullifying previous compromises that had attempted to limit the spread of slavery. This act effectively repealed the Missouri Compromise of 1820, which had prohibited slavery in certain areas, and led to increased tensions and conflicts in the region as pro-slavery and anti-slavery factions clashed, a period often referred to as “Bleeding Kansas.” This decision played a critical role in polarizing the nation leading up to the Civil War, as it spurred intense debates and violence surrounding the issue of slavery's expansion into new territories.