Crisis of the Union

War on Mexico was declared by President James Polk. The opposition against the war by Whigs, which included the son of John Quincy Adams, warned of a conspiracy of the south to add new slave states and maintain control of the government by slave-holding Democrats. This and Polk's expansionist policies split the Democrats into factions.

When gold was discovered in California in 1848, John A. Sutter tried to keep its discovery quiet, but by 1849, more than 80,000 people had came to California. With California's growing population, they were advised to apply for statehood by President Zachary Taylor and were admitted as a free state. This decision led to assertions by John Calhoun about the regulation of slavery in territories and proposals about the Missouri Compromise and the access to western territories by slave owners.

The Fugitive Slave Act was the most controversial part of the Compromise of 1850. It was ignored by free blacks and white abolitionists who helped fugitive slaves escape slave catchers despite threats of fines and imprisonment. Confrontations between slave catchers and free blacks led to the deaths of some slave catchers.

Uncle Tom's Cabin was a novel published by Harriet Beecher Stowe. The book told stories of personal accounts of those in slavery, including one slave as he goes to different slave owners and also two runaway slaves. The book sparked a greater opposition against the Fugitive Slave Act and evoked empathy and outrage in the north.

The Kansas and Nebraska Act brought Kansas in to the Union as a free state and Nebraska as a slave state. The act finished off the Whig party and almost destroyed the Democratic Party. Northern and "anti-Nebraska" Democrats denounced the act as a scheme for extending the supremacy of the slave power and joined Free-Soilers and abolitionists in a new Republican Party.

During Buchanan's presidency, he further widened the split between Democrats and the nation through his actions with the Dred Scott decision and his negotiations to buy Cuba and make it a slave territory. He was also accused of participating in the Slave Power Conspiracy.

Dred Scott was a slave who had lived with his owner in the free state of Illinois and the Wisconsin Territory, where slavery is prohibited by the Northwest Ordinance. He claimed that residence in a free state and territory made him free. Chief Justice Roger Taney's opinion was that any black, whether enslaved or free, could not be a citizen of the United States, which gives Scott no right to sue. This was controversial because some free blacks were citizens. Taney declared the Republicans' anti-slavery policy unconstitutional. Republicans did not accept Taney's arguments and accused him of participating in the Slave Power Conspiracy.

In his campaign for senate against Douglas, Lincoln warned that the proslavery Supreme Court could declare that the constitution does not allow a state to exclude slavery. He predicted that America could not endure as both pro and anti slavery and must become one or the other. The Lincoln and Douglas Debates greatly increased Lincoln's reputation and gave the Republicans control of the House of Representatives in the 1858 election.

John Brown led heavily armed black and white men on a raid on an arsenal in Harpers Ferry, Virginia. The raid was unsuccessful and Democrats called it a result of the beliefs of the Republican Party but anti slavery northerners defended Brown. Before Brown's execution, he warned that the crimes of the south would not be purged away without blood, predicting the Civil War.

In the election of 1860, The Democratic Party chose Douglas as their presidential candidate. The Republicans chose Lincoln. Lincoln won the election with 40 percent of the popular vote and a majority of the Electoral College. Southerners believed the Republican administration would destroy slavery in the south.