Date of Award


Document Type

Union College Only

Degree Name

Bachelor of Arts



First Advisor

Andrea Foroughi




american, exceptionalism, destiny, manifest, citizens


Historians have spent considerable time discussing American Exceptionalism and Manifest Destiny, with good reason. American Exceptionalism is the belief that since its creation, the United States of America and its citizens possess exceptional qualities setting them apart from the rest of the world. Manifest Destiny is the belief that the nation was destined to extend its boundaries from the Atlantic to the Pacific Ocean for its citizens’ benefit. Though both topics have been extensively studied, the historical literature lacks a thorough discussion regarding the connection between these two concepts. This thesis links them by explaining how Jeffersonian ideology shaped notions of American Exceptionalism, which in turn would influence United States policy significantly in early America. By the 1840s, American Exceptionalism continued to flourish as a widely accepted concept and was articulated in geographic terms as Manifest Destiny. Together, American Exceptionalism and Manifest Destiny provided the nation and its citizens with an acceptable rationale for aggressive expansion, which culminated in the Mexican War. The evidence presented in this thesis can be categorized as either public or political sources. Small, partisan newspapers provide a sense of public opinion related to these two concepts. An understanding of the political realm comes from political and military leaders’ public statements, private correspondence, and memoirs, as well as Congressional debates. Analyzing sources from both the public and political spheres is important because political documents contain explicit statements regarding controversial policies, whereas newspaper editorials reveal the implicit motives behind those policies. Before it developed into a powerful program of expansionism, American Exceptionalism had to be characterized in such a way that it would appeal to Americans. Thomas Jefferson accomplished this by simply asserting that virtuous, autonomous citizens were required in order to maintain a successful republic. American Indian policy based on land acquisition was deemed necessary, by first trying to “civilize” American Indians and then expelling the “uncivilized” Indians to create room for the republic and its citizens to prosper. The latter was pursued vigorously under Andrew Jackson’s leadership. The support of expansion by Americans is chronicled in newspaper coverage of the intense election of 1844 that declared Democrat and expansionist James Polk the victor over Whig Henry Clay. Although not all of Polk’s supporters had exceptionalism as their motive for expansion, notably southern slave owners, a considerable amount of northerners wanted to spread republicanism and therefore voted for Polk and the Annexation of Texas, a republic eager to join the United States. In 1845, John O’Sullivan asserted that the exceptional citizens of the U. S. still needed to grow as he declared that the Manifest Destiny of the nation was to extend to the Pacific Ocean. Exceptionalism then took on an aggressive aspect with the onset of the Mexican War. Using Manifest Destiny as both justification and propaganda, the United States waged war against Mexico, certain that the land would be better managed and populated as part of its own Republic. The U.S. government settled for the fulfillment of Manifest Destiny rather than overthrow a sovereign republic. Thus, American Exceptionalism prevented the U.S. from seeking the entirety of Mexico and preserved its identity as a republic inherently superior to a colonial empire.