The Lecompton Constitution was one of four proposed Kansas state constitutions. The Lecompton Constitution supported the existence of slavery in the proposed state and protected rights of slaveholders. In addition, the constitution provided for a referendum that allowed voters the choice of allowing more slaves to the territory. Boycotted by free-staters, the referendum concerning additional slaves to the Kansas territory was passed overwhelmingly. Eventually when President Buchanan attempted to steer the Lecompton Constitution through Congress, it reached a deadlock. A proposal for another referendum gave Kansans the opportunity to either reject or accept the Constitution in its entirety with the proviso that rejection would delay statehood. Despite the proviso, the Constitution was rejected by Kansans, and Kansas was admitted to the Union as a free state in 1861. The Lecompton Constitutional Convention was held on September, 1857 in Lecompton, Kansas Territory. The other proposed state constitutions were the Topeka Constitution, the Leavenworth Constitution and the Wyandotte Constitution.

Democrats opposed to the constitution were known as Anti-Lecompton Democrats.

See also: Historical Background section of Lecompton, Kansas