Final answer:
The debate about slavery in the 19th century between the North and South was primarily about their differing perspectives on the institution.
Step-by-step explanation:
The debate about slavery between the North and South in the 19th century was primarily about their differing perspectives on the institution. The North believed that slavery was morally wrong and incompatible with the principles of liberty and equality. The South, on the other hand, saw slavery as essential to their economy and way of life.
The greatest challenge to this debate was the question of whether slavery should be allowed to expand into new territories and states. This issue became particularly contentious after the U.S. victory over Mexico, as it raised the question of whether slavery would be allowed in the newly acquired lands.
The North argued against the expansion of slavery, believing that it would lead to the entrenchment of the institution and threaten their own economic and political interests. The South, on the other hand, argued for the right to bring slaves into new territories, insisting that to deny them this right would be a violation of their property rights.
The expansion of slavery into new territories posed the greatest challenge to this debate.