The act that would come to supersede the Missouri Compromise right before it ceased to matter at all. Passed in 1854, the Kansas Nebraska Act was initially intended to address the issue of the many miles of open farmland available in the western United States.

A clause of the Act addressed the issue of slavery democratically: state constitutions would be drafted based on popular sovereignty, such that the majority would decide which way a given state would lean.

This is a striking example of why democracy might not be such a good thing, as this clause resulted in the famed Bleeding Kansas incident, in which settlers flooded into Kansas in order to gain a majority for their faction of choice.