Manifest Destiny was a phrase that expressed the idea that the United States was destined to expand from the Atlantic seaboard to the Pacific Ocean; it has also been used to advocate for or justify other territorial acquisitions. Advocates of Manifest Destiny believed that expansion was not only good, but that it was obvious ("manifest") and certain ("destiny"). It was originally a political catch phrase or slogan used by Democrats in the 1845-1855 period, and rejected by Whigs and Republicans of that era. Manifest Destiny was an explanation or justification for that expansion and westward movement, or, in some interpretations, an ideology or doctrine which helped to promote the process. This article is a history of Manifest Destiny as an idea, and the influence of that idea upon American expansion.
The phrase "Manifest Destiny" was first used primarily by Jackson Democrats after 1845 to promote the annexation of much of what is now the Western United States including the Texa