1. Manifest destiny was a widely held cultural belief in the 19th-century United States that American settlers were destined to expand across North America.
2. The philosophy drove 19th-century U.S. territorial expansion and was used to justify the forced removal of Native Americans and other groups from their homes.
3. The rapid expansion of the United States intensified the issue of slavery as new states were added to the Union, leading to the outbreak of the Civil War.
4. Territorial expansion over the first half of the 19th century resulted not only in war with Mexico, but in the dislocation and brutal mistreatment of Native Americans.
