James K. Polk 1795–1849
Mathew Brady (1823?–1896)
Whole-plate daguerreotype, 1849
James K. Polk, the eleventh president of the United States, spent much of his one term in the White House consumed by conflicts in the West. Despite being a Jacksonian Democrat who favored states’ rights over an expanded federal role in political affairs, Polk inherited upon his election in 1844 two issues that demanded a national response. In the Pacific Northwest, questions lingered about the boundary between the United States and Great Britain. After considerable back-and-forth, the two nations agreed upon the forty-ninth parallel, and a crisis was averted.
In the Southwest, though, Polk moved the nation toward war. When Mexican authorities refused to acknowledge the annexation of Texas, Polk directed his secretary of war to advance a military force to the Rio Grande, where hostilities broke out in 1846. In this conflict, the U.S. Army was victorious, and with the signing of the Treaty of Guadalupe Hidalgo in 1848, Polk fulfilled an earlier campaign promise to acquire California.