- The Compromise of 1850: This series of laws aimed to resolve tensions between the North and South by admitting California as a free state, organizing the territories of New Mexico and Utah without specifying whether they would be free or slave states, abolishing the slave trade (but not slavery) in Washington, D.C., and enacting the Fugitive Slave Act, which required citizens to return escaped slaves.
- The Kansas-Nebraska Act of 1854: This law repealed the Missouri Compromise of 1820 and allowed residents of the territories of Kansas and Nebraska to decide for themselves whether they would allow slavery. The act ignited a wave of violence and political turmoil known as "Bleeding Kansas."
- The Dred Scott v. Sandford case of 1857: The Supreme Court ruled that slaves were not citizens and could not sue in federal court. This decision further inflamed tensions between the North and South.
- The Lincoln-Douglas debates of 1858: During the race for the Illinois Senate, Abraham Lincoln and Stephen Douglas engaged in a series of debates on the issue of slavery. These debates helped to bring national attention to the issue and contributed to Lincoln's eventual rise to the presidency.
- The John Brown raid of 1859: Abolitionist John Brown led an armed raid on the federal arsenal at Harpers Ferry, Virginia, with the goal of arming enslaved people and inciting a slave rebellion. The raid failed and Brown was executed, but it further deepened tensions between the North and South.
- The Crittenden Compromise of 1861: This proposal sought to avoid the outbreak of war by extending the Missouri Compromise line to the Pacific Ocean and protecting slavery south of the line. The proposal was rejected by the Republican-controlled Senate and failed to prevent the outbreak of war.
Despite these efforts, the causes of the Civil War—such as the growing divergence between the North and South on issues such as slavery, states' rights, and tariffs— proved too deep to be resolved through political compromise, leading to the outbreak of war in April 1861.