John O’Sullivan first used the term “manifest destiny” in 1845 to describe United States’ annexation of Texas. Although this was the first time this phrase would describe the country’s desire for expansion, it would certainly not be the last instance the term was applicable. Throughout the period antebellum, America underwent expansion that some favored and some disproved. Unfortunately, this would lead to tensions between the two groups, but prompted a more important question: Will these new states be free or cater to slavery? Although the idea of manifest destiny itself was a divisive conflict that contributed to sectionalism, to an even greater extent the civil war and secession resulted from power balance and economic control disputes between free and slave states, as well as strained social relations that further divided northern and southern states.
As America expanded throughout the mid-19th century, more and more controversy arose regarding the newly added territories. The first was the Webster–Ashburton Treaty of 1842, which ended the Aroostook War. Because this was located in close proximity to northern colonies, slavery was not an issue. However, the same cannot be said for other additions to the country. When Texas was annexed in 1845, many southerners were quick to demand the state allow slavery. However, shortly after the Mexican-American war concluded in 1848, Representative David Wilmot introduced his Wilmot Proviso, which stated, “neither slavery nor involuntary servitude shall ever exist in any part of said territory” (Doc B). This was important because it forced politicians to choose sides: would they support the expansion of slavery or not? Ultimately, the Wilmot Proviso passed the house but never the senate. This further shows the political polarization that was rapidly developing in the United States as a result of the slavery issue with new states be admitted and territories being annexed. After the territories became states, even more problems developed. This is especially true of Kansas and Nebraska. The north and the south battled for control, often using violence like John Brown’s attack on Pottawatomie Creek and even physical fights in the senate (Doc F), earning the term “Bleeding Kansas”. When neither side could establish a solid hold, Stephen Douglass proposed the use of popular sovereignty through his Freeport doctrine. Even so, border ruffians proved they would not settle and this became an ongoing conflict, proving each side’s desire to press on whatever the costs may be. Still, it was manifest destiny that led to this conflict in the first place, as the desire to acquire land directly caused the slavery debate to rise to the national spotlight. Another major concern of the United States that accompanied rising political tensions was economic competition. These disputes mainly dealt with land use in acquired territories in the west. Because the South’s economy was focused almost exclusively on cotton, they demanded that land in the west be used to support the “king cotton” empire. In fact, half of US exports at the time were cotton, and about half of the world’s cotton supply came from the US. It seemed like a reasonable way to make a profit, but allowing the land to be used for cotton plantations meant expanding slavery. President Lincoln was unable to accept this. As part of the free-soil party, he wasn’t opposed to slavery’s existence and accepted what was already there, but was starkly against its expansion. He and other free-soilers believed the land and climate of the west was unsuitable for cotton farming. Instead, they believed the west would be best used to support the developing manufacturing industry in the north. A transcontinental railroad was built with the Gadsden purchase to support a developing system of transportation across the country and it’s western territory. This is important because it demonstrates the differing motives each side had in the period of antebellum. While both sides had clear economic goals in mind, the two were very different. The south had their own lifestyle, living on plantations and exporting cotton. This was their vision for the west, but they incurred a significant setback with a stipulation in the compromise of 1850 that eliminated the slave trade in the nation’s capital, Washington, DC. Contrary to that, the north saw the west as an opportunity to expand industry, and they succeeded because congress never made a decisive ruling on slavery in these territories, opening the doors for possibility of secession and the civil war.
Not only were there political and economic detriments that accompanied territorial expansion, but manifest destiny and the slavery debate also fueled increasing social tensions. The most prominent was the uncertainty of a black man’s freedom in the north. Despite being in a free state, many lived in constant fear of being captured and brought to the south, regardless of whether or not they were a runaway slave and belonged down there. This was made possible by the fugitive slave law, a stipulation of the compromise of 1850. It provided that blacks could be captured for simply looking like a runaway slave, or being unable to prove they’re free. This was a major concern for many after the Dred Scott decision that ruled blacks cannot be citizens. In response, locals often formed groups to help protect individuals from this long arm of the law. This clearly shows how there was still a strong sense of unity among people with a common disinterest in laws being passed. One poster warns that blacks must keep a constant “sharp lookout for kidnappers” (Doc C). The abolitionist movement grew significantly in popularity after citizens of the north realized that southerners would go to extreme extents to keep their lifestyle of owning slaves intact. Propaganda was another common method of spreading one’s beliefs, and a particularly successful example was Harriet Beecher Stowe’s novel Uncle Tom’s Cabin (Doc D). This gave people in the north an idea of how slaves were treated and what life on the plantation was like. The book was a harsh wake-up call that sold thousands of copies even in Britain, ultimately causing the British people to disprove of the nation’s possible alliance with the south. Because of this, the British sided with the North after realizing the true effects of the system of slavery in real-life scenarios. Thus, social tensions rose directly due to the issue of slavery and its enforcement in states that it already existed. These applied not only to new territory acquired, but even to states long established with a track record against slavery, showing the wide influence of slavery and its stimulating effects on sectionalism in the Union that ultimately led to secession and the civil war.