Final answer:
Abolitionist literature and speeches significantly impacted the growing opposition to slavery between 1776 to 1850, influencing public opinion and leading to a political and moral confrontation that set the stage for the Civil War.
Step-by-step explanation:
A significant factor contributing to the growing opposition to slavery in the United States from 1776 to 1850 was abolitionist literature and speeches. Leaders such as William Lloyd Garrison brought the evils of slavery into the public consciousness, casting it as a national sin and calling for its immediate end. The growth of abolitionist sentiment was evidenced by the shift from reform to resistance in the 1840s, as abolitionists not only sought to persuade public opinion but also directly aided runaway slaves and established international antislavery support networks. As sectional tensions escalated, particularly with the expansion of the United States westward, fears arose that the balance of power between the North and South would be upset. The violence that marked the 1850s, culminating in John Brown's raid on Harper's Ferry in 1859, indicated that the nation was on the brink of a sectional crisis. The growing political movement to oppose slavery further entrenched the divide as abolitionists and slaveholders dug in their heels for a protracted moral battle over the soul of the country.