Americans felt that the Mexican Cession and Gadsden Purchase fulfilled the goals of Manifest Destiny because these events represented the expansion of U.S. territory and influence across North America. The end of the Mexican-American War led to growth in the United States’ landholdings, as Mexico ceded California and the Southwest to the United States. This acquisition was seen as a significant step in fulfilling the belief that Americans were destined to spread across the continent.
The Gadsden Purchase further solidified this vision by connecting the United States from the Atlantic Ocean to the Pacific Ocean, facilitating commerce and settlement along the southern route. Together, these territorial gains were viewed as an embodiment of Manifest Destiny, as they fulfilled aspirations for expansion, economic opportunity, and the spread of democratic ideals.