How did manifest destiny influence political decisions during 1840s?

Manifest Destiny significantly influenced political decisions in the 1840s by promoting the belief that the expansion of the United States across North America was both justified and inevitable. This ideology fueled territorial acquisitions, such as the annexation of Texas and the Oregon Territory, and intensified debates over slavery in new territories. Politicians, driven by Manifest Destiny, often prioritized expansionist policies, which ultimately contributed to the sectional tensions that led to the Civil War. Overall, it shaped U.S. foreign policy and domestic politics, emphasizing a national mission to spread democracy and civilization.