The U.S. acquired the Oregon Territory in the era of Manifest Destiny, but new lands increased tensions over the issue of slavery. One key outcome of these tensions was the Kansas-Nebraska Act of 1854 and 'Bleeding Kansas,' which further escalated conflicts that led to the Civil War.
One of the territories the United States acquired during the Manifest Destiny era (1840s-1850s) was the Oregon Territory in 1846, which the U.S. obtained via a treaty with Britain. This acquisition, along with others such as the Texas Annexation and the Mexican Cession, actually enhanced tensions within the country. The major issue was whether these new territories should permit slavery, a question that fueled discord between the North and the South.
One significant outcome of these tensions between 1850 and 1860 was the Kansas-Nebraska Act of 1854, which allowed the settlers in those territories to decide for themselves whether or not to allow slavery. This resulted in significant violence and conflict in these regions, a period called 'Bleeding Kansas.” The mounting sectional discord eventually played a role in triggering the American Civil War in 1861.
Learn more about Manifest Destiny