Mexican War, 1846–48, armed conflict between the United States and Mexico.

Causes

While the immediate cause of the war was the U.S. annexation of Texas (Dec., 1845), other factors had disturbed peaceful relations between the two republics. In the United States there was agitation for the settlement of long-standing claims arising from injuries and property losses sustained by U.S. citizens in the various Mexican revolutions.

Another major factor was the American ambition, publicly stated by President Polk Polk, James Knox (pōk), 1795–1849, 11th President of the United States (1845–49), b. Mecklenburg co., N.C.
..... Click the link for more information. , of acquiring California, upon which it was believed France and Great Britain were casting covetous eyes. Despite the rupture of diplomatic relations between Mexico and the United States that followed congressional consent to the admission of Texas into the Union, President Polk sent John Slidell Slidell, John (slīdĕl`, slī`dəl), 1793–1871, American political leader and diplomat, b. New York City.
..... Click the link for more information. to Mexico to negotiate a settlement. Slidell was authorized to purchase California and New Mexico, part of which was claimed by Texas, and to offer the U.S. government's assumption of liability for the claims of U.S. citizens in return for boundary adjustments.

When Mexico declined to negotiate, the United States prepared to take by force what it could not achieve by diplomacy. The war was heartily supported by the outright imperialists and by those who wished slave-holding territory extended. The settlement of the Oregon boundary dispute (June, 1846), which took place shortly after the official outbreak of hostilities, seemed to indicate British acquiescence, for it granted the United States a free hand.

The Course of Hostilities

Early in May, 1845, American troops under Gen. Zachary Taylor Taylor, Zachary (zăk`ərē), 1784–1850, 12th President of the United States (1849–50), b. Orange co., Va.
..... Click the link for more information. had been stationed at the Sabine River preliminary to an advance to the Rio Grande, the southern boundary claimed by Texas. They advanced to Corpus Christi in July. In Mar., 1846, after the failure of Slidell's mission, Taylor occupied Point Isabel, a town at the mouth of the Rio Grande. To the Mexicans, who claimed the Nueces River as the boundary, this was an act of aggression, and after some negotiations Gen. Mariano Arista ordered his troops to cross the Rio Grande. On Apr. 25 a clash between the two armies occurred, and Taylor reported to Washington that hostilities had begun.

On May 3 the guns of Matamoros began to shell Fort Brown (then Fort Taylor), an advanced American position near the present Brownsville, Tex. President Polk called these Mexican actions an invasion of American soil, and on May 13, 1846, the United States declared war. Meanwhile, Taylor had defeated the Mexicans at Palo Alto Palo Alto, locality not far from Brownsville, Tex., where the first battle of the Mexican War was fought on May 8, 1846. American troops under Gen. Zachary Taylor defeated a Mexican force led by Gen. Mariano Arista, who retreated to Resaca de la Palma.
..... Click the link for more information. (May 8) and Resaca de la Palma Resaca de la Palma (rāsä`kä thā lä päl`mä)
..... Click the link for more information. (May 9). The Mexicans retreated across the Rio Grande. Taylor followed them and on May 18 took Matamoros. After a delay he then advanced on Monterrey, which he occupied after a five-day battle (Sept. 20–24, 1846).

In June, 1846, Gen. Stephen W. Kearny Kearny, Stephen Watts, 1794–1848, American general in the Mexican War, b. Newark, N.J. At the beginning of the Mexican War he was made commander of the Army of the West with the rank (June, 1846) of brigadier general.
..... Click the link for more information. left Fort Leavenworth for New Mexico with some 1,600 men, including a force of Missouri volunteers under Alexander Doniphan Doniphan, Alexander William (dŏn`ĭfən), 1808–87, American lawyer and soldier, b. Mason co., Ky.
..... Click the link for more information. . Santa Fe was taken (August), a provisional government was set up, and Doniphan was placed in command of the area. Kearny pushed on to California to find that this province, through the agency of Commodore John D. Sloat Sloat, John Drake, 1781–1867, American naval officer, b. near Goshen, N.Y. He entered the navy as a midshipman in 1800 and resigned after a year's service, but reentered for service in the War of 1812.
..... Click the link for more information. (later relieved by Robert F. Stockton Stockton, Robert Field, 1795–1866, American naval officer, b. Princeton, N.J. He left the College of New Jersey (now Princeton) to enter the U.S. Navy at 16 and served in the War of 1812 and in the subsequent campaigns against the Barbary pirates.
..... Click the link for more information. ) and John C. Frémont Frémont, John Charles, 1813–90, American explorer, soldier, and political leader, b. Savannah, Ga. He taught mathematics to U.S. naval cadets, then became an assistant on a surveying expedition (1838–39) between the upper Mississippi River and the
..... Click the link for more information. , was already under American rule. After reinforcements reached Santa Fe, Doniphan invaded (Dec., 1846) N Mexico, taking El Paso and Chihuahua before he joined forces with Gen. John E. Wool (who had advanced southwest from San Antonio) and with Taylor at Saltillo.

Gen. Antonio López de Santa Anna Santa Anna, Antonio López de (äntō`nyō lō`pās dā sän`tä ä`nä)
..... Click the link for more information. , who had been in exile in Cuba and had been allowed passage through the U.S. blockade at Veracruz, had now assumed the presidency of Mexico; he gathered a large force to stop Taylor's advance. Taylor, whose army had been greatly reduced in size, was in an extremely vulnerable position when hit by Santa Anna in the battle of Buena Vista Buena Vista, battle of, military engagement in the Mexican War, fought Feb. 22–23, 1847. The battle site was just S of Saltillo, Coahuila, in Mexico. Gen. Zachary Taylor , disobeying orders from the U.S. government, had advanced here. Gen.
..... Click the link for more information. (Feb., 1847). The fighting was hard and appeared indecisive for a time, but in the end the Mexicans withdrew in confusion.

The final campaign of the war began with the landing of U.S. forces under Gen. Winfield Scott Scott, Winfield, 1786–1866, American general, b. near Petersburg, Va.

Military Career

He briefly attended the College of William and Mary, studied law at Petersburg, and joined the military.
..... Click the link for more information. at Veracruz in Mar., 1847. Scott was supported by a naval task force under David Conner (who was relieved by Matthew C. Perry Perry, Matthew Calbraith, 1794–1858, American naval officer, b. South Kingstown, R.I.; brother of Oliver Hazard Perry. Appointed a midshipman in 1809, he first served under his brother on the Revenge and then was aide to Commodore John Rodgers on the
..... Click the link for more information. ); they landed some 12,000 men and after a three-day bombardment took the city. Scott then began his drive on Mexico City. In April, Santa Anna was defeated at the mountain stronghold of Cerro Gordo Cerro Gordo (sā`rō gōr`thō)
..... Click the link for more information. . After hard fighting Mexican forces were also routed at Contreras Contreras (kōntrā`räs), village, central Mexico, near Mexico City, site of an important battle (Aug.
..... Click the link for more information. and Churubusco (August).

On Aug. 24 the Mexicans accepted an armistice, but after two weeks of futile peace negotiations, fighting was resumed. The Mexican capital was heavily defended by garrisons at Casa Mata and Molino del Rey and by the great fortress of Chapultepec Chapultepec (chäp
..... Click the link for more information. . William J. Worth Worth, William Jenkins, 1794–1849, American army officer, b. Hudson, N.Y. He served with distinction on the Niagara frontier in the War of 1812 and later became commandant of cadets and instructor of infantry tactics at West Point (1820–28), even though
..... Click the link for more information. carried Casa Mata and Molino del Rey, and the supposedly impregnable Chapultepec was stormed in a savage American assault led by Gen. John A. Quitman Quitman, John Anthony, 1798–1858, American general and politician, b. Rhinebeck, N.Y. He settled in Natchez, Miss., where he practiced law and held a series of political offices, serving in the state legislature and as acting governor (1835–36).
..... Click the link for more information. . On Sept. 14, 1847, American troops entered Mexico City, where they remained until peace was restored.

The Settlement

The United States had won an easy victory, partly because Mexico, torn by civil strife, could not present a united front to face the invader. The Mexican presidency had changed hands a number of times during the war, and some Mexican states had refused to cooperate with the central government. Peace negotiations were conducted on behalf of the United States by Nicholas P. Trist Trist, Nicholas Philip, 1800–1874, American diplomat, b. Charlottesville, Va. He attended West Point, studied law under Thomas Jefferson, whose granddaughter he married, and was private secretary to Andrew Jackson. He served as U.S.
..... Click the link for more information. , a secret envoy, whose relations with General Scott were at first strained. Although recalled by President Polk, Trist decided to ignore the order and continue his negotiations, which resulted in the Treaty of Guadalupe Hidalgo Guadalupe Hidalgo (gwäthäl
..... Click the link for more information. (Feb. 2, 1848). By the terms of the treaty, Mexico ceded to the United States two fifths of its territory and received an indemnity of $15 million and the assumption of American claims against Mexico by the U.S. government. The boundary between the two countries, as outlined, was to follow the Rio Grande from its mouth to the New Mexico line, then run west to the Gila River, follow the Gila to the Colorado River and then follow the boundary between Upper California and Lower California to the Pacific.

Bibliography

See G. L. Rives, The United States and Mexico, 1821–1848 (1913, repr. 1969); J. H. Smith, The War with Mexico (1919, repr. 1963); B. De Voto, The Year of Decision (1943, repr. 1961); A. H. Bill, Rehearsal for Conflict (1947, repr. 1969); R. S. Henry, The Story of the Mexican War (1950, repr. 1961); O. A. Singletary, The Mexican War (1960); R. E. Ruiz, The Mexican War: Was It Manifest Destiny? (1963); D. M. Fletcher, The Diplomacy of Annexation (1973); K. J. Bauer, The Mexican War (1974); J. H. Schroeder, Mr. Polk's War (1974), G. N. Brack, Mexico Views Manifest Destiny (1975), and J. M. McPherson, Battle Cry of Freedom (1988).

Mexican War

or Mexican-American War

(1846–48) War between the U.S. and Mexico. It grew from a border dispute after the U.S. annexed Texas in 1845; Mexico claimed that the southern border of Texas was the Nueces River, while the U.S. claimed it was the Rio Grande. A secret mission by John Slidell to negotiate the dispute and purchase New Mexico and California for up to $30 million was aborted when Mexico refused to receive him. In response to the snub, Pres. James Polk sent troops under Zachary Taylor to occupy the disputed land between the two rivers. In April 1846 Mexican troops crossed the Rio Grande and attacked Taylor's troops; Congress approved a declaration of war in May. Ordered to invade Mexico, Taylor captured Monterrey and defeated a large Mexican force under Antonio Santa Anna at the Battle of Buena Vista in February 1847. Polk then ordered Gen. Winfield Scott to move his army by sea to Veracruz, capture the city, and march inland to Mexico City. Scott followed the plan, meeting resistance at Cerro Gordo and Contreras, and entered Mexico City in September. Under the Treaty of Guadalupe Hidalgo, Mexico ceded to the U.S. nearly all of present New Mexico, Utah, Nevada, Arizona, California, Texas, and Colorado for $15,000,000 and U.S. assumption of its citizens' claims against Mexico. Casualties included about 13,000 American deaths, all but 1,700 of which were caused by disease. The war, which made a national hero of Taylor, reopened the slavery-extension issue supposedly settled by the Missouri Compromise.