Bleeding Kansas began with the Kansas-Nebraska Act of 1854. It created territories of Kansas and Nebraska by Senator Stephen A. Douglas and President Franklin Pierce. Its initial purpose was to open up thousands of new farms but also allowed the states to vote whether slavery was legal or not.
People from the South who supported slavery wanted Kansas to become a slave state. People from the South who didn't support slavery wanted Kansas to stay free.
Keep Kansas free!
We want slaves!
When the act was passed, armed Southerners crossed the border of Missouri. Armed settlers also came from the North and the East and an election was held. Men flooded over the boundary of Missouri and out-voted the anti-slavery settlers in Kansas, and then went home. The legislature adopted the same laws of Missouri as the laws of Kansas.
Abolitionist John Brown led anti slavery fighters in an attack on Harpers Ferry. This civil conflict led to more political polarization. This was to be expected because the frontier area was compounded by the activities of pro-slavery Missourians and those in the North that wanted slaves to be free. Hostility ran rampant across the Kansas-Missouri Border and between pro slavery activists and abolitionists.
In late 1855 thousands of Missourians attacked the free-state stronghold of Lawrence and in 1856 the entire town was looted. In response John Brown led the attack and murder of five pro-slavery activists. After that, four months of violence continued to ensue.
John Geary who was appointed territorial governor of Kansas cooled the border war with the help of federal troops. Although the border war cooled down Kansas did not stop bleeding. Disorder was announced in 1858 and free men were being killed. All pro-slavery in Kansas was rejected in the same year and even though this happened small skirmishes continued to happen until the beginning of the Civil War.