Which event did John Brown mistakenly think would provoke a slave uprising in the South?

John Brown mistakenly believed that his raid on Harper's Ferry would ignite a widespread slave uprising in the South. His intent was to arm enslaved people, hoping they would rise against their masters and overthrow the institution of slavery. Brown envisioned that the successful seizure of the armory would inspire others to join him in the fight for freedom. However, the raid did not result in the anticipated uprising; instead, it was met with resistance and ultimately led to his capture and execution. This event significantly heightened tensions between the North and South and played a role in the lead-up to the Civil War.

While the abolition of slavery, the Lincoln-Douglas debate, and the election of Lincoln were all pivotal events related to the issue of slavery, they did not play a direct role in Brown's belief about provoking an immediate revolt among enslaved people.