Final answer:
John Brown was an abolitionist that Henry David Thoreau characterized as a martyr, whose actions polarized public opinion between the North and South prior to the Civil War. The North saw him as a principled figure against slavery after his trial, while the South regarded him as a threat and terrorist.
Step-by-step explanation:
John Brown was a radical abolitionist whose actions before the American Civil War raised substantial debate regarding his tactics and intentions. A deeply religious man and a staunch opponent to slavery, Brown is often remembered for his raid on Harpers Ferry and his willingness to use violence to end the institution of slavery. Henry David Thoreau characterized John Brown as a martyr and a man of principles in his speech, and asked his fellow citizens to recognize the moral imperative behind Brown's actions. In Thoreau's view and the view of many northerners, especially after Brown's composure during his trial and execution, Brown embodied the fight against the moral evil of slavery.
The public opinion in the North began to shift as Brown's demeanor throughout his capture, trial, and execution painted him as a principled martyr, rather than just a criminal. This opinion was in stark contrast to the southern view, where Brown was regarded as a terrorist threatening their way of life, intensifying the discussions on secession due to the fear of further abolitionist aggression. Thus, Brown's actions and the response to his execution significantly contributed to the polarization of the nation in the lead-up to the Civil War.
On one hand, the southerners viewed John Brown as a dangerous insurgent bent on inciting rebellion, provoking martial law and a more aggressive pro-slavery stance in the South. On the other hand, many northerners, influenced by Brown's calculated sacrifice, began to view Brown not as a terrorist but as a symbol of resistance against the entrenched power of slavery, leading to an amplified discussion about abolition and equality.