Which ideology supports the belief that the U.S. should expand its territory across North America and beyond?

The belief that the U.S. should expand its territory across North America and beyond is best captured by the ideology known as Manifest Destiny. This concept emerged in the 19th century and reflected the idea that it was the divine right and destiny of the United States to expand its territory from the Atlantic to the Pacific Ocean. Manifest Destiny was rooted in a sense of American exceptionalism, suggesting that the nation had a mission to spread democracy and capitalism across the continent and into other regions.

This ideology played a critical role in justifying the westward expansion, including events such as the annexation of Texas, the Oregon Trail migration, and the Mexican-American War. Proponents of Manifest Destiny believed that expansion was not only beneficial for the U.S. but also a moral imperative to bring about civilization and progress.

The other concepts, while related to national attitudes and policies, do not specifically encapsulate the idea of territorial expansion in the same way. Isolationism represents a reluctance to engage in international affairs, expansionism refers more broadly to the act of growing in territory or influence, and nationalism emphasizes pride in one's country without inherently expressing the idea of territorial expansion as a divinely ordained mission.