The document summarizes key events that increased tensions between the North and South leading up to the Civil War, including westward expansion, debates over the spread of slavery to new territories, the passage of fugitive slave laws, the Dred Scott decision, the emergence of the Republican Party, and John Brown's raid. Ultimately, Abraham Lincoln's election in 1860 prompted several Southern states to secede and form the Confederate States of America, marking the start of hostilities when Confederate forces fired on Fort Sumter in South Carolina in 1861.