Mexican Cession (1848)

views updated


The Treaty of Guadalupe-Hidalgo was the peace treaty between the United States and Mexico that officially ended the Mexican War (18461848). The conflict lasted until the treaty was signed on February 2, 1848, in Guadalupe Hidalgo, a city in south central Mexico near Mexico City. The core of the treaty defined the "Mexican Cession," the territory that Mexico was obliged to cede to the United States as a result of the war.

The Mexican War was the culmination of a series of conflicts between Mexico and the United States. These included the 1836 War of Independence of Texas from Mexico, the 1845 annexation of Texas by the United States, and the claims of United States citizens for monetary damages against the Mexican government. (A group of citizens of the United States claimed they had been injured and their property had been damaged during the civil strife that followed Mexico's 1821 war of national liberation against Spain.) In addition, the Mexican and U.S. governments disagreed over the southern boundary of Texas. The Mexicans contended that the Nueces River was the boundary, while the Texans claimed that the dividing line was further south and west, along the Rio Grande River. Another important source of conflict was the determination of the United States to acquire California. California was a Mexican province where, by 1845, about 700 United States citizens had settled. The United States claimed that if it did not annex California the territory might come under French or British rule.

To this must be added the racial and cultural tensions that developed between these mid-nineteenth century descendants of Spanish and English colonization.

Centuries of subjugation of Indian people by the Spanish had produced the rich cultural and racial amalgamation of the Mexican people. The Spanish influence was communicated through a network of Catholic missions that spanned what is now the southwestern United States. These Catholic missions were also centers of economic life. Gradually, as Mexico developed its own social structure, the Catholic missions were replaced as the focus of economic and social life by large haciendas, the seat of a nascent Mexican aristocracy.

This aristocracy of ranchers and farmers led the Mexican Revolution against the Spanish in 1821. After the revolution, in the interest of economic development of its northern, thinly settled provinces, the Mexican government invited settlers to Texas. The Mexican land-owners who were already there engaged in agriculture and ranching until the influx of Anglo-Americans in the 1830s and, in California, especially after the gold rush of 1849. This influx of North Americans turned out to be a disaster, not only for the Mexican nation during the Mexican-American War, but also for the individual Mexican land-owners in Texas and California. Their land was simply taken from them.

Thus it was with some sense of injured pride that Mexico broke off diplomatic relations with the United States when the U.S. annexed Texas in 1845. President James K. Polk (17941849) sent General Zachary Taylor (17841850) across the Nueces river to enforce U.S. claims on Texas' southern boundary. President Polk dispatched John Slidell, a Louisiana politician and trader, to accompany the invading army with instructions to purchase the land in dispute. He offered $5 million for New Mexico and $25 million for California. The Mexican government refused to discuss this proposal. As a result, General Zachary Taylor advanced to the mouth of the Rio Grande River, 120 miles south. The Mexican government sent troops across the Rio Grande saying that Taylor was engaged in an act of aggression. President Polk proclaimed that the Mexican army had invaded United States soil and, on May 13, 1846, Congress declared war on Mexico.

In a distinct improvement over their record during the War of 1812 (18121814), the armed forces of the United States performed well during the war. Contending with rugged terrain and logistical problems, the U.S. force of 14,000 prevailed over the Mexican military force. They occupied Mexico City in September, 1847.

In light of this military success President Polk began to set his sights on annexing all of Mexico. An obscure, low level U.S. agent, Nicolas Trist, scuttled this ambitious goal when he negotiated the treaty of Guadalupe-Hidalgo for the U.S. side. President Polk was outraged when he learned that Trist had secured only the original U.S. demands. Still in the Treaty of Guadalupe-Hidalgo Mexico lost nearly one million square miles of landalmost one-half of its territory. This territory, termed the "Mexican Cession," included land that makes up the states of California, Nevada, New Mexico, Utah, Arizona, Texas, and parts of Colorado and Wyoming. The Mexican government received $15 million and the promise that the United States would settle all claims of its citizens against Mexico. These claims amounted to more than $3 million. The Mexican citizens in this acquired territory were presumed to be legal U.S. citizens unless they vacated the area or registered as Mexican citizens within a one-year time frame. The treaty also granted the citizens in this area religious freedom, property, and civil rights. Article IX stated that Mexican citizens in this territory "shall be incorporated into the United States of America, and admitted as soon as possible, according to the principles of the Federal Constitution, to the enjoyment of all the rights of citizens of the United States. In the meantime, they shall be maintained and protected in the enjoyment of their liberty and property, and the civil rights now vested in them according to the Mexican laws."

In light of the delicate balance in Congress between the slave states and the wage-labor states, the acquisition of this land from Mexico re-kindled the debate in Congress over slavery. Southerners hoped to enlarge the territory that would enter the union as slave states. Anti-slavery northerners feared that very outcome. For that reason many northerners from both parties opposed the war with Mexico. The Mexican cession thus played a part in the nation's drift towards the Civil War.

See also: Manifest Destiny, Sun Belt, Westward Expansion


Hornblower, Margot. "Northern Exposure." Time, March 6, 1995.

O'Rourke, David K. "Our War with Mexico: Rereading Guadalupe Hidalgo." Commonweal, March 13, 1998.

Rodriguez, Roberto. "Treaty of Guadalupe-Hidalgo under New Scrutiny." Black Issues in Higher Education, April 30, 1998.

Singletary, Otis A. The Mexican War. Chicago: University of Chicago Press, 1960.

About this article

Mexican Cession (1848)

Updated About content Print Article