Final answer:
John Brown sought to initiate a slave uprising by seizing weapons from Harpers Ferry's arsenal to distribute to enslaved people, but his plan was thwarted and led to his capture and execution.
Step-by-step explanation:
John Brown's objective with his raid on Harpers Ferry arsenal in October 1859 was to seize weapons and distribute them among enslaved people to begin a massive uprising aimed at ending slavery. Brown's approach, marked by the violence he had shown during the Pottawatomie attack in Kansas, was in stark contrast to the pacifist abolitionists of his time. His raid, although initially successful in capturing the arsenal, failed to incite the broad slave rebellion he envisioned. The effort ended with Brown's capture by federal troops led by Colonel Robert E. Lee, followed by Brown's execution for treason.