The territory of Kansas is admitted into the Union as the 34th state, or the 28th state if the secession of eight Southern states over the previous six weeks is taken into account. Kansas, deeply divided over the issue of slavery, was granted statehood as a free state in a gesture of support for Kansas' militant anti-slavery forces, which had been in armed conflict with pro-slavery groups since Kansas became a territory in 1854.
Trouble in territorial Kansas began with the signing of the 1854 Kansas-Nebraska Act by President Franklin Pierce. The act stipulated that settlers in the newly created territories of Nebraska and Kansas would decide by popular vote whether their territory would be free or slave. In early 1855, Kansas' first election proved a violent affair, as more than 5,000 so-called Border Ruffians invaded the territory from western Missouri and forced the election of a pro-slavery legislature. To prevent further bloodshed, Andrew H. Reeder, appointed territorial governor by President Pierce, reluctantly approved the election. A few months later, the Kansas Free State forces were formed, armed by supporters in the North and featuring the leadership of militant abolitionist John Brown.
During the next four years, raids, skirmishes, and massacres continued in "Bleeding Kansas," as it became popularly known. The territory's admittance into the Union in January 1861 only increased tension, but just three and a half months later the irrepressible differences in Kansas were swallowed up by the full-scale outbreak of the American Civil War. During the Civil War, Kansas suffered the highest rate of fatal casualties of any Union state, largely because of its great internal divisions over the issue of slavery.