Manifest destiny main subject United States territorial acquisitions
Era of continental expansion
The phrase "manifest destiny" is most often associated with the territorial expansion of the United States from 1812 to 1867. This era, from the War of 1812 to the acquisition of Alaska in 1867, has been called the "age of manifest destiny". During this time, the United States expanded to the Pacific Ocean—"from sea to shining sea"—largely defining the borders of the continental United States as they are today.The United States, while intending never to acquire lands from the Indians otherwise than peaceably, and with their free consent, are fully determined, in that manner, progressively, and in proportion as their growing population may require, to reclaim from the state of nature, and to bring into cultivation every portion of the territory contained within their acknowledged boundaries. In thus providing for the support of millions of civilized beings, they will not violate any dictate of justice or of humanity; for they will not only give to the few thousand savages scattered over that territory an ample equivalent for any right they may surrender, but will always leave them the possession of lands more than they can cultivate, and more than adequate to their subsistence, comfort, and enjoyment, by cultivation. If this be a spirit of aggrandizement, the undersigned are prepared to admit, in that sense, its existence; but they must deny that it affords the slightest proof of an intention not to respect the boundaries between them and European nations, or of a desire to encroach upon the territories of Great Britain... They will not suppose that that Government will avow, as the basis of their policy towards the United States a system of arresting their natural growth within their own territories, for the sake of preserving a perpetual desert for savages.
A shocked Henry Goulburn, one of the British negotiators at Ghent, remarked, after coming to understand the American position on taking the Indians' land: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.
Adams did much to further this idea. He orchestrated the Treaty of 1818, which established the Canada–U.S. 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.
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 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, done in conjunction with the Walter Hines Page School of International Relations, Albert Weinberg wrote: "the expansionism of the [1830s] arose as a defensive effort to forestall the encroachment of Europe in North America".