History: American Civil War (1861-1865)

The 1854 Ostend Manifesto was an unsuccessful Southern attempt to annex Cuba as a slave state. The Second Party System broke down after passage of the Kansas-Nebraska Act in 1854, which replaced the Missouri Compromise ban on slavery with popular sovereignty, allowing the people of a territory to vote for or against slavery. The Bleeding Kansas controversy over the status of slavery in the Kansas Territory included massive vote fraud perpetrated by Missouri pro-slavery Border Ruffians. Vote fraud led pro-South Presidents Franklin Pierce and James Buchanan to attempt to admit Kansas as a slave state. Buchanan supported the pro-slavery Lecompton Constitution.
Violence over the status of slavery in Kansas erupted with the Wakarusa War, the Sacking of Lawrence, the caning of Republican Charles Sumner by the Southerner Preston Brooks, the Pottawatomie Massacre, the Battle of Black Jack, the Battle of Osawatomie and the Marais des Cygnes massacre. The 1857 Supreme Court Dred Scott decision allowed slavery in the territories even where the majority opposed slavery, including Kansas.
The Lincoln-Douglas debates of 1858 included Northern Democratic leader Stephen A. Douglas' Freeport Doctrine. This doctrine was an argument for thwarting the Dred Scott decision that, along with Douglas' defeat of the Lecompton Constitution, divided the Democratic Party between North and South. Northern abolitionist John Brown's raid at Harpers Ferry Armory was an attempt to incite slave insurrections in 1859. The North-South split in the Democratic Party in 1860 due to the Southern demand for a slave code for the territories completed polarization of the nation between North and South.