From the inception of America in 1776 to the mid-1800s, there was a balance between regions of the country. That dramatically changed throughout the 1840s and 1850s.
With the industrialization of the North and the absence of industrialization of the South, a divide emerged between the two. See David Potter, The Impending Crisis: America Before the Civil War, 1848-1861, 33. Throughout this period of time, the North had a “more rapid rate of growth than the South, with the result that the North drew steadily further ahead of the South in population.” Id.
Soon after that development, some historians argue that the South began to develop “signs of fear that it would be overpowered” as a collective. Id. citing Jesse T. Carpenter, The South as a Conscious Minority, 1789-1861 (New York, 1930), 7-33. Some believe this fear led to a “sense of solidarity, apartness, and defensiveness, and caused the elaboration of the perennial southern political doctrines of states’ rights.” David Potter, The Impending Crisis: America Before the Civil War, 1848-1861, 33.
With the expansion of the country westward, this was only exacerbated. As new territory was being acquired throughout the first decades of the 1800s, the South became increasingly determined to expand the presence of slavery. See id. at 33-34. The insecurity of the South as a collective, so the theory goes, came as a result of the North’s success and the country’s acquisition of new territory.
Certainly, to some extent, Americans in the South had developed concerns about the future of the country. Those concerns were centered on feeling threatened by the North’s activities. The expansion of the country through war and otherwise ensured that folks in the South would be continuously reminded of who was winning this battle between expanding the influence of the North and the South.
As a general matter, this was setting southerners up for problems, particularly as the North continued to enjoy success in barring the expansion of slavery. This would culminate in the years leading up to the Civil War when the North and South would increasingly bicker over the treatment of territories acquired and the expansion of slavery.
Had the North contemplated that its actions would lead the South down this line of thinking, perhaps those in the North would have chosen otherwise. Nonetheless, as every gain was made by the North, that was only emboldening those in the South to take action and prevent the spread of free states in the Union, no matter the cost.