Bleeding Kansas, Bloody Kansas or the Border War was a series of violent political confrontations in the United States involving anti-slavery "Free-Staters" and pro-slavery "Border Ruffian", or "southern yankees" elements in Kansas between 1854 and 1861, including "Bleeding Congress". The Kansas–Nebraska Act of 1854 called for "popular sovereignty"—that is, the decision about slavery was to be made by the settlers (rather than outsiders). It would be decided by votes—or more exactly which side had more votes counted by officials. At the heart of the conflict was the question of whether Kansas would allow or outlaw slavery, and thus enter the Union as a slave state or a free state. Pro-slavery forces said every settler had the right to bring his own property, including slaves, into the terr