Manifest Destiny
As photographic techniques and medias further developed in the 20th century, including smaller cameras, celluloid film that did not need to be processed in the field, and pre-made silver gelatin printing paper, arguments for the expansion of the U.S.'s political and military terrain reaching to the western coast of the continent was characterized as both inevitable and popularly justified through photographs collected by a growing middle class. After Thomas Jefferson negotiated the Louisiana Purchase in 1803–which conveniently allowed the exchange of more than 500 million acres of land from the French, in spite of the fact the French did not own, or even occupy most of the territory–photographs like Jackson’s depicting Indigenous lands along the Oregon Trail as unused and ripe for development by Anglo Americans, coupled with images that depicted native peoples as a ‘vanishing race’ (Jackson also participated in the construction of this genre), convincingly coaxed millions of people from the eastern U.S., China and Mexico to seek “freedom” in the midland and western realms of the continent.
Manifest Destiny and the American West at the National Gallery of Art