What ideology justified American expansionism, suggesting that it was the nation's destiny to expand across the continent?

Manifest Destiny is the ideology that justified American expansionism in the 19th century by suggesting that it was the nation’s divine right and destiny to expand its territory across North America. This belief was rooted in a combination of nationalism and a sense of mission, often interpreted as a religious calling, which posited that the United States had a unique role in spreading democracy and civilization. Proponents of Manifest Destiny believed that American culture and governance were superior and should be extended westward, which was reflected in various historical actions, including territorial acquisitions and the displacement of Native American populations.

This ideology was instrumental in driving policies and events such as the annexation of Texas, the Oregon Trail migration, and the Mexican-American War, all of which were viewed as steps toward fulfilling this perceived destiny. The concept of Manifest Destiny not only shaped American attitudes and policies but also contributed to the complex narratives of American expansionism, including the often harsh realities it created for those whose lands and lives were affected by this pursuit.