Mexican-American War

Manifest Destiny

Manifest destiny rationalized U.S. expansion westward that began in the 1820s. It was a religious and racial ideology that expressed the supremacy of particular forms of Christianity and democratic capitalism as manifestations of God's divine providence. Although some writers and politicians supported the notion that the United States was destined to expand across the continent, there were others in the United States, namely northern abolitionists, who expressed their reservations about entering into a war with Mexico and whether the United States was acting righteously in relation to a newly formed neighbor, or seeking to expand the number of slave states in the union. Others questioned the possible outcomes of including so many new people into the nation so quickly who were nonwhite and non-Christian.

This was one of the key dilemmas of manifest destiny: The doctrine called for American expansion into the west, and some even envisioned a United States that encompassed the whole of the continent; however, it was vague about the fate of the non-Americans already living in those lands. This ambivalence, with some policies favoring [Page 1456]assimilation and others annihilation, was characteristic of the 19th century.

An 1851 painting by Carl Nebel shows the American occupation of Mexico City during the final days of the Mexican-American War. Combat operations lasted a year and a half with American forces quickly occupying New Mexico and California. Several garrisons on the Pacific Coast further south in Baja, California, were taken while another army captured Mexico City, and the war ended in U.S. victory.

The Battle for Texas Independence at the Alamo, Goliad, and San Jacinto reflected a fundamental dispute over land ownership, manifest destiny, and immigrant rights in Mexico between its independence from Spain in 1821 and the loss of the territory in 1836. The Mexican-American War has its roots in Texas. Encouraging Anglo-Americans to settle in the area starting in 1822, the Mexican government required settlers to support Mexico and Catholicism in exchange for 5,000-acre grants of land. Anglo-American settlers bristled against Mexican laws and culture from the beginning, showing outright resistance to Mexico's abolition of slavery in 1829. The call to arms given by settler Stephen Austin in 1835 ultimately ended in Mexico's loss of Texas in April 1836.

Texas remained an independent republic, centered in the heart of the Mexican nation, until 1845, at which point it was annexed by the United States through a joint resolution of Congress; it was eventually admitted as the 28th state of the union. In 1846, U.S. and Mexican troops fought on a strip of disputed land between the two nations located between the Nueces River and the Rio Grande. President James K. Polk declared war in May 1846, asserting that it was the only recourse. Often forgotten were the initial conditions upon which Americans agreed to settle in the territory.

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