What belief justified the 19th-century expansion of the United States across the Americas?

The belief that justified the 19th-century expansion of the United States across the Americas is known as Manifest Destiny. This concept centered around the idea that it was the inevitable and divinely ordained destiny of the United States to expand its territory and influence across the North American continent. Proponents of Manifest Destiny viewed expansion as a means to spread democracy and capitalism, asserting that the United States had a unique role in establishing a "more perfect union" through growth and territorial acquisition.

Manifest Destiny was fueled by a sense of nationalism and a belief in the superiority of American culture and institutions. This ideology played a crucial role in motivating various events, such as the westward migration, the annexation of Texas, and the acquisition of territories following the Mexican-American War. The embrace of this belief helped to justify actions that resulted in significant changes to the American landscape, including the displacement of Native American populations and conflicts over land ownership.

In contrast, while Social Darwinism, American Exceptionalism, and Colonial Imperialism relate to concepts of superiority and expansion, they do not encapsulate the specific belief system that drove the 19th-century expansionist fervor in the same way that Manifest Destiny does. They each have different historical contexts and implications that do not directly address the motivations