Final answer:
Henry Clay's American System increased sectional tensions due to its endorsement of protective tariffs, internal improvements, and the expansion of slavery, which favored some regions over others, leading to a national divide that contributed to the Civil War.
Step-by-step explanation:
The American System, devised by Henry Clay, played a significant role in heightening sectional tensions in the early to mid-19th century. This system, which promoted a protective tariff, a national bank, and internal improvements, was meant to benefit the whole nation. However, the protective tariff was contentious, as it advantaged northern manufacturers while disadvantaging southern and western farmers, who faced higher prices for goods and international retaliatory tariffs on agricultural products. The disparities in regional interests contributed to an increasingly fractured national landscape.
The American System's championing of internal improvements was also a point of conflict as it raised issues of states' rights versus federal authority. The federal government's active role in the economy was met with suspicion, particularly among citizens in the southern states. The perceived regional favoritism and federal overreach sewed discord. Moreover, by endorsing the expansion of slavery into new territories and states, the American System set the stage for further confrontations between abolitionist northern states and pro-slavery southern states.
Thus, what was intended to unify and strengthen the nation economically ended up contributing to the polarization between the North and the South. The opposition to the American System was a factor that led to the formation of new political alignments and eventually set the stage for the deepening divide that precipitated the Civil War.