In the election of 1860 , the issue of slavery split apart the:

The election of 1860 was crucial as it highlighted the deep divisions in the United States over the issue of slavery, leading to a dramatic split in the Democratic Party. Northern Democrats, who supported Stephen A. Douglas, advocated for popular sovereignty, while Southern Democrats rallied around John C. Breckinridge, who endorsed the expansion of slavery into the territories. This divide not only reflected regional tensions but also set the stage for the Civil War, which would erupt just months after Abraham Lincoln's election. As the election unfolded, it marked the beginning of new political alignments, ultimately leading to the formation of the Republican Party, which opposed the expansion of slavery. This party's rise showcased the increasing influence of anti-slavery sentiments in the North. Additionally, the fragmented electoral outcome meant that Lincoln was elected without securing a single Southern electoral vote, further illustrating the stark geographical polarization over the contentious issue of slavery.