Battle of Buena Vista, lithograph by Currier & Ives, c. 1847. Image from Library of Congress.

The Mexican War Erupts, 1846

On May 13, 1846, United States president and North Carolina native James K. Polk signed a declaration of war on Mexico.

At the time of the 1844 election, many Americans advocated an expansionist vision of the nation’s future, popularly known as “Manifest Destiny.” Complicating the issue was a growing dispute over the possible expansion of slavery into any territories acquired by the United States.

The 1846 declaration of war against Mexico. Image from the National Archives.

Controversy centered on the possible annexation of the Republic of Texas, which had revolted against Mexico in 1836. As Texas was a slaveholding republic, its potential incorporation was a political flashpoint. Polk ran on a platform advocating for the annexation of the Lone Star State.

Upon taking office in March 1845, Polk signed an annexation treaty with Texas. Tensions between the U.S. and Mexico simmered over the Texas boundary which came to head in April 1846 when fighting erupted between Mexican and U.S. forces in the disputed zone.

The resulting Mexican-American war led to the U.S. conquest of all Mexican territory north of the Rio Grande.

The conflict also began a series of increasingly heated controversies over whether that territory would become slave or free, culminating in the Civil War.

Visit: The President James K. Polk Historic Site near Charlotte interprets significant events in the Polk administration, including the Mexican-American War.

Images from Library of Congress and National Archives.

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