Guadalupe Hidalgo, Treaty of

(1848)

   The treaty ending the Mexican War of 1845-1848 and transferring over half of the Mexican territory to the United States. Negotiated by Nicholas P. Trist for the United States and Luis Gonzaga Cuevas, Bernardo Couto, and Miguel Aristrain for Mexico, the treaty was signed on February 2, ratified by the U.S. Senate on March 10 and the Mexican government on May 30, and proclaimed July 4, 1848. American interest in territory south of the Louisiana Purchase had been longstanding. In 1836, Texas declared itself independent of Mexico, and in 1845 the United States annexed Texas. After a clash between American and Mexican troops on Mexican territory, Congress declared war on May 13, 1846. American troops captured Mexico City on September 17, 1847, and Trist, without official authorization, opened negotiations later that year.

   By the treaty, Mexico ceded what later became Arizona, California, New Mexico, Texas, and parts of Colorado, Nevada, and Utah, to the United States, in all some 55 percent of Mexican territory. Washington compensated Mexico with $15 million for war-related damages to Mexican property and assumed up to $3.5 million of claims by American citizens against Mexico. The border was set at the Rio Grande and the two nations agreed to cooperate on any future road, canal, or railway project along the Gila River, later the basis of the 1853 Gadsden Purchase.

   The treaty benefited mainly the United States, which completed, except for the Gadsden Purchase of 1853, its contiguous continental expansion by increasing its national territory by approximately one-quarter. Many Americans viewed the treaty as a validation of the nation’s Manifest Destiny to expand across the continent, but the terms soured Mexican-American relations for decades and the territorial acquisition exacerbated sectional divisions in the United States. The treaty and the circumstances surrounding it exemplify America’s antebellum expansionist thrust.

   FURTHER READING:

    Hunter Miller, ed. Treaties and other International Acts of the United States of America. Vol. V. Washington: U.S. Government Printing Office, 1937, pp. 207–428;

    Pletcher, David M. The Diplomacy of Annexation: Texas, Oregon, and the Mexican War. Columbia: University of Missouri Press, 1973.

   KENNETH J. BLUME