Because James Polk vowed to serve only one term, he tried to achieve specific goals quickly. Many of these goals were centered on his campaign platform of expanding the United States westward.
Polk oversaw the annexation of Texas; settlement of the Oregon boundary dispute with Great Britain, which led to the acquisition of territory that became Washington, Oregon, Idaho, and parts of Montana and Wyoming; acquisition of territory from Mexico that eventually became California, New Mexico, Arizona, Nevada, Utah, and parts of Colorado and Wyoming; and reestablishment of an independent treasury system. What happened when Polk initially tried to acquire California and New Mexico?