After the United States acquired Texas, President James K. Polk intentionally provoked a conflict with Mexico primarily to obtain California. Polk recognized the strategic and economic advantages of acquiring this territory and believed that military action was necessary to achieve that goal. His ambitions were not merely about territorial expansion but were rooted in a vision of American growth.

Historian George Bancroft later recounted Polk's assertion that the acquisition of California was essential, illustrating Polk's determination. This belief in Manifest Destiny drove the nation towards war, which ultimately resulted in significant territorial gains for the United States. The actions taken under Polk's leadership reflect a pivotal moment in American expansionist policy.