Final answer:
The Kansas-Nebraska Act led to "Bleeding Kansas" as it allowed popular sovereignty to decide on slavery in the territory, causing violent conflict between proslavery and antislavery factions aiming to influence the state's status.
Step-by-step explanation:
The Kansas-Nebraska Act of 1854 led to violence known as "Bleeding Kansas" because it allowed the settlers of Kansas to decide whether they would be a free or a slave state through popular sovereignty. This decision nullified the Missouri Compromise, which had prohibited slavery north of latitude 36°30'. As a result, proslavery and antislavery supporters rushed into Kansas to influence the vote, leading to violent clashes between the two sides.
The act not only involved the concept of popular sovereignty but was also seen as a direct challenge to the established political balance between free and slave states. The pressure to secure Kansas as either free or slave territory became a highly contentious issue, leading to acts of violence by guerrilla forces and abolitionists alike, culminating in over 150 deaths. This turbulence was a precursor to the American Civil War, making the region a battleground for the national crisis over slavery, highlighting the high stakes and the volatile nature of the slavery debate.