Final answer:
The dissolution of the Union over slavery involved economic, political, and ideological differences between the North and South. Key events that intensified these divisions included the westward expansion of slavery, the Dred Scott decision, the Lincoln-Douglas debates, and the election of Lincoln, cumulating in Southern secession.
Step-by-step explanation:
The issues surrounding slavery that contributed to the dissolution of the Union leading up to the Civil War were complex and multifaceted. The economic dependency of the South on slavery for crop production created an ideological rift with the North, which did not rely on slave labor for economic prosperity. This economic disparity tied to racial and political issues was a significant factor that divided the nation geographically and ideologically.
The Sectional Crisis emerged due to conflicts over the westward expansion of slavery and the role of the federal government in protecting slaveholders' interests. In the North, there was a belief that slavery suppressed wages and took away land that could have been used by poor whites for economic independence. Concurrently, the South feared the loss of slavery's expansion would lead to the abolitionist faction gaining control of national politics and potentially provoke slave insurrections.
The dissolution of the Union was a protracted process, with critical events including the Missouri Compromise, the Dred Scott decision, the Lincoln-Douglas debates, and John Brown's raid on Harper's Ferry exacerbating divisions. The Compromise of 1850 and the admission of California as a free state added fuel to the fire. These events, along with the election of Abraham Lincoln in 1860, prompted South Carolina and other Southern states to secede, leading to the Civil War.