U.S. Forces Capture Mexico City

Context

The Mexican-American War arose from long-standing territorial disputes between the United States and Mexico. The U.S. annexation of Texas in 1845, which Mexico still claimed, combined with American interest in acquiring California and other western lands, produced repeated diplomatic failures. President James K. Polk pressed for a settlement that Mexico rejected, leading to the outbreak of hostilities in 1846 along the disputed Rio Grande border.

What Happened

After early northern campaigns under Zachary Taylor, Polk authorized an expedition under Winfield Scott to strike directly at the Mexican capital. Scott executed the first large-scale amphibious landing in U.S. history at Veracruz in March 1847, then advanced inland through a series of hard-fought victories at Cerro Gordo, Contreras, and Churubusco. By early September his forces stood before Mexico City. On September 8 and 12–13 the Americans captured the fortified positions of Molino del Rey and Chapultepec Castle after intense fighting that included Mexican military cadets among the defenders. On the morning of September 14, Scott’s troops marched into the city center; a small party raised the Stars and Stripes over the National Palace, known to Americans as the Hall of the Montezumas. Mexican President and General Antonio López de Santa Anna withdrew with the remnants of his army, leaving the capital under U.S. occupation.

Aftermath

Major combat operations largely ceased after the fall of the capital, although guerrilla resistance and street skirmishes continued during the nine-month occupation. Santa Anna resigned and went into exile; a new Mexican government formed to negotiate peace. American forces secured supply lines back to Veracruz while U.S. diplomats, chiefly Nicholas Trist, conducted talks that would produce the Treaty of Guadalupe Hidalgo.

Legacy

The occupation of Mexico City forced Mexico to accept the loss of roughly half its territory in the 1848 treaty, including present-day California, Nevada, Utah, Arizona, New Mexico, and parts of Colorado and Wyoming. The vast acquisition accelerated U.S. westward expansion and reinforced the doctrine of Manifest Destiny. In Mexico the war remains a symbol of national loss and foreign intervention, while in the United States it is remembered both as a triumph of arms and as a conflict that intensified sectional tensions over slavery in the newly acquired lands.