FTCE Subject Area Practice Test 2026 – Comprehensive Prep Guide

John O'Sullivan is the figure closely associated with the promotion of westward expansion in the United States because he coined the term "Manifest Destiny" in the 1840s. This concept encapsulated the belief that Americans were destined to expand across North America, spreading their values and culture. O'Sullivan's writings and arguments helped to justify the aggressive territorial expansion that characterized the era, influencing public opinion and policy.

His advocacy for Manifest Destiny was pivotal during a time when the United States was considering annexing Texas and pushing into territories occupied by Native Americans and other nations. O'Sullivan's contributions established a cultural and ideological framework that legitimized the westward movement and underscored the sense of national mission that many Americans felt.

While the other figures listed had roles in U.S. history, they are not primarily recognized for the same level of influence regarding the ideology of westward expansion as O'Sullivan. For instance, Thomas Jefferson played a key role in the Louisiana Purchase, which significantly expanded U.S. territory but did not articulate the broader ideology of Manifest Destiny. Similarly, Andrew Jackson's presidency was marked by policies that affected westward expansion, but his focus was more on governance and military actions rather than the ideological promotion of expansion itself. James