Final answer:
Manifest Destiny contributed to the American Civil War by intensifying the debate over the expansion of slavery into newly acquired territories, disrupting the balance between free and slave states, and exacerbating sectional tensions to the point where compromises like the Missouri Compromise and the Kansas-Nebraska Act could no longer prevent conflict.
Step-by-step explanation:
Some historians contend that Manifest Destiny played a significant role in rekindling sectional tensions which ultimately led to the American Civil War. Manifest Destiny, a term coined in the 1840s, represented the belief that the United States was divinely ordained to expand across North America. This expansionist movement led to the acquisition of territories such as Texas and Oregon, and further inflamed the debate over the expansion of slavery.
The addition of new territories posed the question of whether these would be free or slave states, threatening the balance maintained by the Missouri Compromise. The delicate balance was further disrupted by the Kansas-Nebraska Act, which many argue was a significant event pushing the nation toward conflict. The growing disagreement over the spread of slavery was not purely a moral debate but was intertwined with economic interests, cultural differences, and political power.
By the time Abraham Lincoln was elected in 1860, sectional divisions had become so deep that compromise seemed impossible. Southern states feared the loss of slave labor which was integral to their economy and societal structure. As tensions peaked, with Lincoln's election viewed as a threat to slavery, seven Deep South states seceded, forming the Confederacy and setting the stage for the Civil War with the attack on Fort Sumter.