Explain popular sovereignty and what happen when it was actually put into practice?

Popular sovereignty is the principle that the authority of a government is created and sustained by the consent of its people, emphasizing that the power rests with the electorate. This concept was notably applied during the mid-19th century in the context of U.S. territories, where it was used to determine whether new states would be free or slave states, particularly in the Kansas-Nebraska Act of 1854. When put into practice, it led to violent conflict, most famously in "Bleeding Kansas," as pro-slavery and anti-slavery factions clashed over control, highlighting the difficulties and dangers of allowing local populations to make such divisive decisions. Ultimately, the implementation of popular sovereignty contributed to the tensions that precipitated the Civil War.