What does the term "Manifest Destiny" refer to?

The term "Manifest Destiny" refers to the belief that the United States was destined to expand its territory throughout North America. This concept emerged in the 19th century and was used to justify westward expansion, under the notion that it was both a natural right and a divine sanction for Americans to spread across the continent. Advocates of manifest destiny argued that it was the nation's duty to bring democracy and civilization to the lands they settled, often at the expense of Native American populations and other nations.

Understanding this belief helps clarify the motivations behind significant historical events during this period, including the annexation of Texas, the Oregon Trail's migration, and the Mexican-American War. The notion greatly influenced U.S. policies and attitudes regarding territorial expansion, making it a key element in American history. This framing of expansion as a moral imperative underscores why this answer is the most appropriate in capturing the essence of manifest destiny.