Final answer:
Prior to the Civil War, events such as Bleeding Kansas, the attack on Charles Sumner, and John Brown's Raid on Harpers Ferry increased Northern and Southern animosity. The 1856 presidential election, heavily centered on the issue of slavery, further divided the nation, setting the stage for Lincoln's election and eventual secession of Southern states.
Step-by-step explanation:
Violent events prior to the Civil War escalated animosity between the North and the South, significantly influenced by the divisive issue of slavery. One notable incident was the conflict known as Bleeding Kansas, a series of bloody confrontations in the Kansas Territory where pro-slavery and anti-slavery forces clashed over the state's slavery status. Another critical event was the attack on Senator Charles Sumner by Representative Preston Brooks, an act of violence on the Senate floor that symbolized the breakdown of civil discourse. Similarly, John Brown's Raid on Harpers Ferry added to the violent tensions, as Brown sought to initiate a slave revolt.
The presidential election of 1856 had slavery as a pivotal issue. The Republican Party emerged with a platform opposing the expansion of slavery into the territories, a stance that alarmed the South and contributed to growing sectional tensions. While the Democrats won with James Buchanan, the unsettling effect of the Republican position on slavery foreshadowed the eventual election of Abraham Lincoln in 1860, which led to Southern secession and the onset of the Civil War. These events underscored the deep divisions regarding the institution of slavery and the political, social, and economic control it imparted.