One reason the Missouri Compromise did not have lasting effects was that it only temporarily resolved the issue of slavery in newly acquired territories. As the United States continued to expand westward, new territories were acquired and the question of whether they would allow slavery or not continued to arise. This ultimately led to further conflicts and the eventual breakdown of the compromise with the passage of the Kansas-Nebraska Act in 1854, which repealed the prohibition on slavery in territories north of the 36° 30' parallel established by the Missouri Compromise. This further fueled tensions between the North and South and ultimately contributed to the outbreak of the Civil War.
