How was the Civil War in Kansas related to the dispute over the westward expansion of slavery?

During the Antebellum, the US federal government was constantly dealing with the issue of slavery and where it should/should not exist. One of the territories where this was the case was Kansas. In order to make this decision more democratic, the US Congress passed the Kansas-Nebraska Act. This allowed the citizens to vote on whether or not they would have slavery.

This worked out terribly, as massive voter fraud and violence ensued when the votes were counted and it was determined that Kansas would be a slave territory. However, the people against slavery in Kansas felt the election was unfair and made their own constitution. This constant battle between people who did and did not want slavery resulted in "Bleeding Kansas." This period of violence in Kansas represented the strong feelings of citizens in regards to slavery.