<P> The 19th - century belief that the United States would eventually encompass all of North America is known as "continentalism," a form of tellurocracy . An early proponent of this idea, John Quincy Adams, became a leading figure in U.S. expansion between the Louisiana Purchase in 1803 and the Polk administration in the 1840s . In 1811, Adams wrote to his father: </P> <P> The whole continent of North America appears to be destined by Divine Providence to be peopled by one nation, speaking one language, professing one general system of religious and political principles, and accustomed to one general tenor of social usages and customs . For the common happiness of them all, for their peace and prosperity, I believe it is indispensable that they should be associated in one federal Union . </P> <P> Adams did much to further this idea . He orchestrated the Treaty of 1818, which established the Canada--US border as far west as the Rocky Mountains, and provided for the joint occupation of the region known in American history as the Oregon Country and in British and Canadian history as the New Caledonia and Columbia Districts . He negotiated the Transcontinental Treaty in 1819, transferring Florida from Spain to the United States and extending the U.S. border with Spanish Mexico all the way to the Pacific Ocean . And he formulated the Monroe Doctrine of 1823, which warned Europe that the Western Hemisphere was no longer open for European colonization . </P> <P> The Monroe Doctrine and "manifest destiny" formed a closely related nexus of principles: historian Walter McDougall calls manifest destiny a corollary of the Monroe Doctrine, because while the Monroe Doctrine did not specify expansion, expansion was necessary in order to enforce the Doctrine . Concerns in the United States that European powers (especially Great Britain) were seeking to acquire colonies or greater influence in North America led to calls for expansion in order to prevent this . In his influential 1935 study of manifest destiny, Albert Weinberg wrote: "the expansionism of the (1830s) arose as a defensive effort to forestall the encroachment of Europe in North America". </P>

The concept that it is a god-given right to spread out across the continent is called what