What contributed to the events of "Bleeding Kansas" was the competition of opposing political groups, regarding the issue of slavery.
It encompasses a series of violent political and popular confrontations between 1854 and 1861, in the Kansas Territory and the western border towns of Missouri, between anti-slavery "Free Staters" and "Border Ruffians", supporters of slavery.
The events of Bleeding Kansas led directly to the American Civil War and conditioned relations between Kansas and Missouri.