The term manifest destiny originated in the 1840s. It expressed the belief that it was Anglo-Saxon Americans’ providential mission to expand their civilization and institutions across the breadth of North America. This expansion would involve not merely territorial aggrandizement but the progress of liberty and individual economic opportunity as well.
It was, O’Sullivan claimed, ‘our manifest destiny to overspread the continent allotted by Providence for the free development of our yearly multiplying millions.’ The term and the concept were taken up by those desiring to secure Oregon Territory, California, Mexican land in the Southwest, and, in the 1850s, Cuba. Originally a partisan Democratic issue, ‘manifest destiny’ gained Republican adherents as time passed. By the end of the century, expansionists were employing quasi-Darwinist reasoning to argue that because its ‘Anglo-Saxon heritage’ made America supremely fit, it had become the nation’s ‘manifest destiny’ to extend its influence beyond its continental boundaries into the Pacific and Caribbean basins.
The Reader’s Companion to American History. Eric Foner and John A. Garraty, Editors. Copyright © 1991 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.