Mexican War

Mexican War, conflict between the United States and Mexico, lasting from 1846 to 1848. The war resulted in a decisive U.S. victory and forced Mexico to relinquish all claims to approximately half its national territory. Mexico had already lost control of much of its northeastern territory as a result of the Texas Revolution (1835-1836). This land, combined with the territory Mexico ceded at the end of the war, would form the future U.S. states of Arizona, California, Nevada, New Mexico, Texas, and Utah, as well as portions of the states of Colorado, Kansas, Oklahoma, and Wyoming. See United States (History): War with Mexico.

Mexico’s territorial losses signified the end of any likelihood that Mexico, rather than the United States, would become the predominant power in North America. As the first conflict in which U.S. military forces fought almost exclusively outside of the country, the Mexican War also marked the beginning of the rise of the United States as a global military power.

Many Mexicans, meanwhile, deeply resented their loss to the “Colossus of the North,” viewing the conflict as an unnecessary war that had been thrust upon Mexico by a land-hungry United States. This nurtured a fear of the United States—sometimes bordering on hatred—among some Mexicans that has been kept alive and popularized through corridos, the folk ballads of Mexico. More positively, the war also generated a new feeling of patriotism and national pride in the young nation, evidenced today by the pilgrimages to Chapultepec Park in Mexico City every September 13 to honor the young military cadets (Niños Héroes) who chose to die rather than surrender to U.S. troops at the end of the war.

BACKGROUND

The two major issues behind the war were the inability of the Mexican government to establish political and economic control over its vast northern frontier, including the Mexican state of Tejas y Coahuila, and the westward movement and dynamic expansionism of the United States during the 19th century.

Lack of Mexican Control

Under Mexico’s first national charter, the constitution of 1824, the territories of Coahuila and Texas were established as one Mexican state: Tejas y Coahuila. However, the central government in Mexico City had enormous difficulty exercising direct control over events in these northern regions of the country, due to a variety of problems. The most important of these were civil war and religious turmoil.

The 1820s and early 1830s saw a number of military rebellions in Mexico in which federalists, who supported constitutional democracy and wanted to limit the power of the Roman Catholic Church, clashed with centralists, who wanted a centralized dictatorship based in Mexico City and opposed reforms intended to weaken the church. In 1835 the federal republic was overthrown by centralists. The next year the 1824 constitution was replaced by laws which concentrated political power in the capital and took power away from the states. For the next decade, various competing factions of centralists controlled the Mexican government. The political turmoil of this period, as well as the centralization of power in Mexico City, made it difficult for the Mexican government to exercise its authority in the northern frontier regions such as Texas.

This weak political control was matched by the decline of Catholic religious authority in the region in the late 1700s and early 1800s. In the 18th century, the Spanish Crown moved to limit the wealth and power of Franciscan and Jesuit religious orders by taking over much of their property. The Jesuits were expelled from the Spanish colonies in 1767, and their buildings and property were auctioned off by the Crown. The federalists who wanted to limit the power of the Catholic Church were also hostile to the Franciscan order, which caused many Franciscans to flee to Europe.

By the 1820s the number of missionaries in the northern frontier regions had dropped off sharply. The Catholic Church did not have the funds nor the clergy to fill the void after the Jesuit and Franciscan missionaries left the frontier. By 1846 the church’s presence on the Mexican frontier had diminished, with empty parishes in places where friars once proudly served. Because one of the primary goals of the missionaries was to convert Native Americans to Christianity and pressure them to adopt Hispanic customs, the decline of the religious orders also meant a decline in the influence of Hispanic culture and Catholicism in the region.

U.S. Expansion

After 1821 the northern regions of Mexico became increasingly integrated with the United States. Before Mexico won independence from Spain in 1821, Spain had forbidden trade between Santa Fe, in the New Mexico territory, and the United States. After independence, Mexico began to encourage trade. The inauguration of the Santa Fe Trail in 1821 linked Independence, in western Missouri, to Santa Fe and extended the Missouri trade into Chihuahua, a city in north central Mexico. This growing trade led the northern Mexican provinces to seek manufactured goods from the United States rather than areas in southern Mexico.

At the same time, the United States was expanding aggressively. President James K. Polk (1845-1849) and his administrators sought trade outlets to the Pacific Ocean and had their eyes on the coasts and bays of Texas, Oregon and California. Land-hungry settlers were moving across the Mississippi River into the cotton fields and cattle lands of Louisiana and East Texas. Fur trappers and New England merchants were looking for pelts and hides along the Gila River—which runs through the current U.S. states of Arizona and New Mexico—and moved from there into southern California.

The westward migration of U.S. citizens was encouraged by Manifest Destiny, a belief that territorial expansion by the United States was both inevitable and divinely ordained. Those who believed in Manifest Destiny also believed that the culture of the United States was superior to other cultures and that republican forms of government and democracy should be expanded in order to “civilize” other peoples. Although Manifest Destiny was criticized by some people as blatantly racist, it enjoyed support among U.S. citizens and politicians in the mid- and late 1800s.

THE ROAD TO WAR

Central to the events leading up to war were the Fredonian Rebellion (1826), the Texas Revolution (1835-1836), and the annexation of Texas by the United States in 1845.

The Fredonian Rebellion

In 1825 a group of Texas colonists received permission from the Mexican government to colonize an area in eastern Texas known as Nacogdoches. By the time they arrived, however, other settlers had already claimed the region. The Texas colonists threatened to expel anyone who could not produce a valid land title. After the original settlers protested, the Mexican government denied the Texans permission to colonize the region.

In December 1826 a group of 16 Texas colonists went to Nacogdoches and proclaimed the region to be the independent Republic of Fredonia. The next month about 60 men, mostly Mexicans, rode to Nacogdoches to capture the rebellious Fredonians. The small garrison of Fredonians soundly defeated their attackers in the only battle of the rebellion. When Mexican troops arrived at Nacogdoches a short time later, the republic had been dissolved and the leader of the colonists had fled to Louisiana.

The Texas Revolution

Although the Fredonians were not successful, by the 1830s the population of Mexican Texas included many immigrants from the United States. These Anglo-American colonists were angry over Mexican attempts to deny autonomy to Texas and were unhappy with a colonization law that prevented immigration from the United States into Texas. They were also wary of Catholic laws and customs. In 1835 they revolted and established Texas as an independent republic. The Texas Revolution included the battles of The Alamo, Goliad, and San Jacinto. When hostilities ceased, Mexican General Antonio López de Santa Anna agreed to withdraw his troops across the Río Grande and recognize the independence of Texas. The Mexican congress rejected the agreement, and many Mexicans assumed the nation would regain Texas. It soon became apparent, however, that Mexico was in no position to retake Texas by force. The Lone Star Republic, as it was known, remained independent from 1836 to 1845, when the United States Congress approved a joint resolution annexing Texas. Mexico considered this annexation an act of aggression, and the Mexican diplomat in Washington, D.C., broke off negotiations and went home.

Disputed Borders

With diplomatic relations broken, President Polk sent diplomat John Slidell as a special envoy to Mexico to negotiate a dispute over the boundary between Texas and Mexico. Throughout the colonial era the western boundary of Spanish “Tejas” had been the Nueces River. During the Mexican period of Texas history, from 1821 to 1845, Spanish and Mexican maps and documents reaffirmed the Nueces River as the boundary. But the Anglos in Texas, and their backers in the United States, insisted that the western boundary was the Río Grande. At stake were not merely the 150 miles that separated the Nueces from the Río Grande in southern Texas, but the thousands of square miles of territory to the northwest that also fell within the claim (including half of New Mexico, several hundred miles west of the headwaters of the Nueces River).

But when Mexican newspapers discovered that Slidell also had secret instructions to negotiate for the purchase of California and New Mexico, they threatened rebellion if Mexican president José Joaquin de Herrera negotiated with the United States. The president promptly informed Polk that he had nothing to discuss with Slidell. Herrera was then overthrown by General Mariano Paredes, and Mexico prepared to assert its authority over Texas by mobilizing an army of 5200 troops near the mouth of the Río Grande under the command of General Mariano Arista.

On June 23, 1845, General Zachary Taylor, in command of approximately 1500 regulars, was ordered to leave Louisiana for Texas. By July he was in Corpus Christi, about 320 km (200 mi) north of the Río Grande. That next year, on March 8, 1846, Polk ordered Taylor and his troops to enter disputed territory between the Nueces and the Río Grande. Another detachment was moved to Fort Texas (present-day Brownsville, Texas), across the border from Matamoros, Mexico. By April 1846 the two nations stood on the brink of war.

THE WAR

On April 24 Taylor’s forces clashed with Arista’s at Carricitos on the northern bank of the Río Grande. Polk used this skirmish to justify his war message to Congress when he declared that Mexico had “shed American blood on American soil.” Although a young congressman from Illinois named Abraham Lincoln challenged Polk to show him the spot where blood had been shed, a majority of the members of Congress were ready to approve a bill authorizing war.

On May 8, before Polk signed the declaration of war, the first major engagement of the Mexican War began. This was the Battle of Palo Alto, which took place along the Gulf Coast north of Matamoros and the Río Grande. Taylor pitted his approximately 2200 troops against Arista’s 3200 Mexican soldiers. The U.S. artillery inflicted heavy casualties on the Mexicans while Taylor reported only 16 men killed or wounded. The next day another pre-war battle occurred south of Palo Alto at Resaca de la Palma, sending the Mexicans reeling back to Matamoros. Finally, on May 13, Polk signed a declaration of war, and five days later Matamoros fell to the United States. Arista retreated and was relieved of his command.

The U.S. strategy called for a three-pronged offense: The Army of the West would take New Mexico and California; the Army of the Center would seize northern Mexico; and the Army of Occupation would carry the war into Mexico City. The navy would provide logistical support, escort the transport of troops to Mexico, guard the army’s bases from the sea, and blockade the coasts along the Gulf of Mexico and the Pacific. It would also aid the capture of Monterey, a key coastal port in central California, and assist in the capture and occupation of Tampico and Veracruz on Mexico’s Gulf Coast.

California and New Mexico

General Stephen W. Kearny, commanding the Army of the West, was the first to mobilize, when his army of 1500 men departed Fort Leavenworth, Kansas, in June of 1846 and began the 900-mile trek to Santa Fe. With the Mexicans evacuating the town before the U.S. troops arrived on August 19, Kearny was able to take Santa Fe without firing a shot. Although the occupation was initially peaceful, U.S. troops were soon harassed by Mexican and Native American (primarily Pueblo) attacks. After August 19, Kearny divided his army into three groups in order to attack or control various strategic locations simultaneously. One contingent would remain to pacify Santa Fe, while another, under Colonel Alexander William Doniphan, was dispatched south to Chihuahua in north central Mexico. The third group, under Kearny’s command, was sent west to California to assist U.S. forces already fighting there.

In the meantime, U.S. settlers in northern California had revolted against Mexican rule in June of 1846, before news of the declaration of war had even reached them. Led by Colonel John C. Frémont, the settlers captured a fort at Sonoma, north of San Francisco, and proclaimed the establishment of the Bear Flag Republic. The republic was shortlived, however. On July 7, 1846, naval commodore John D. Sloat, commander of U.S. naval forces along the Pacific Coast, ordered the U.S. flag raised at Monterey, about 140 km (87 mi) south of San Francisco, and formally claimed California for the United States. A few days later, U.S. forces occupied the port of San Francisco. Sloat, in poor health, transferred his command of the naval forces to Commodore Robert Stockton in late July.

When Kearny and his troops finally arrived in southern California in December, U.S. forces had already captured Los Angeles, but had been driven out a short time later. On December 6, Kearny’s army fought Mexican troops under Captain Andrés Pico. Kearny was wounded and his troops almost annihilated. In January U.S. forces attacked and recaptured Los Angeles, forcing the surrender of hundreds of Mexicans and effectively ending Mexican resistance in California.

Northern Mexico

Meanwhile, in August 1846, Taylor’s Army of the Center, now 6000 strong (half of whom were Texas volunteers) had moved through Camargo toward the city of Monterrey in northwestern Mexico. General Pedro Ampudia commanded the troops protecting Monterrey. While he was preparing the defenses of the city, centralist President Paredes was overthrown in Mexico City by federalist forces, including General Santa Anna, who had returned from exile in Cuba. The federalists promptly restored the 1824 constitution. General Ampudia, evidently influenced by the fall of Paredes, became indecisive and added to the confusion and demoralization of his troops. The battle began in September, and after three days of fierce fighting, Taylor was able to outflank the Mexicans and begin closing in on the city. On September 25 the fighting was over, and General Ampudia asked for a truce. Taylor agreed to permit the Mexican army to withdraw from the city and an eight-week truce began. The arrival of Doniphan, whose forces had attacked and occupied Chihuahua, fortified Taylor’s base and made most of northern Mexico secure for U.S. forces. After President Polk criticized the leniency of the truce, Taylor informed General Santa Anna that he would end the agreement before the eight weeks were up.

In early 1847 about half of Taylor’s troops were reassigned to General Scott to help in the attack on Veracruz. Santa Anna learned of Taylor’s weakened position and immediately began marching an army of 18,000 to 20,000 men north from San Luis Potosí in central Mexico in hopes of catching him by surprise. Taylor was alerted of the march, however, and prepared his defenses at Buena Vista, about 70 km (45 mi) west of Monterrey. Only about 15,000 of Santa Anna’s troops completed the march; the rest had died, been abandoned, or deserted along the way. The two armies met in February 1847, with the Mexican forces outnumbering U.S. troops three to one. Although Santa Anna’s assaults on Taylor’s defenses did much damage and Mexican troops almost overran the U.S. positions, Taylor’s artillery performed well and the attack was eventually repulsed. Although both sides would claim victory, the battle ended in a stalemate. Santa Anna, with a few war trophies in hand (some flags and three cannons), withdrew from the battlefield to resolve a dispute in Mexico City, leaving northern Mexico to the invaders.

Mexico City

Despite defeat in the north and constant political bickering in Mexico City, the Mexicans were still unwilling to sue for peace. Believing it impractical to march across the desert south of Monterrey, the U.S. military command ordered Taylor to reassign the best half of his troops (the regulars) to General Winfield Scott, the man selected to occupy Veracruz on the Gulf Coast.

In March 1847 Scott’s Army of the Occupation, with some 10,000 men, landed on the Mexican coast south of the harbor of Veracruz. The invasion was accompanied by a bombardment that launched approximately 6700 shells at the city. Hundreds of Mexican civilians were killed. Civilian corpses piled up in the streets; buildings, including hospitals, were gutted by fire; and a yellow-fever epidemic raged. After two days, the siege was over, and the Stars and Stripes replaced the Eagle and Serpent of the Mexican flag. While 67 Americans had been killed or wounded, the Mexican civilian and military dead numbered between 1000 and 1500. Civilian casualties outnumbered their military counterparts 2 to 1.

Santa Anna had just arrived in Mexico City when news of the Veracruz defeat arrived. He secured from the Catholic Church a promise of a loan to finance the army and then rushed off toward Veracruz to meet the U.S. troops that were heading west to Mexico City. The opposing forces met in mid-April at a mountain pass near Cerro Gordo, about 80 km (about 50 mi) northwest of Veracruz. Scott outflanked the Mexicans and attacked from the rear. The Mexican defense soon disintegrated, and Santa Anna barely escaped capture. He fled west to Puebla, but the citizens there would not cooperate with him. When Santa Anna went on to Mexico City, Scott and his army took Puebla unopposed.

While Scott’s troops rested for the summer in Puebla, Santa Anna went about preparing the defenses of Mexico City. With the Mexican states refusing to lend money to the federal government, and the city government uncooperative, the capital was placed under martial law. To combat the U.S. forces, the Mexican army organized several companies of foreign residents and deserters from the U.S. Army into units that were known as San Patricios (Saint Patricks).

In August the war came to the outskirts of Mexico City, with engagements at Contreras and Churubusco. In both instances the U.S. forces were superior in leadership, tactics, and technology. At Churubusco, in late August, the Mexicans fought bravely and refused to yield ground to the better-equipped Americans. The battle was won with hand-to-hand combat.

One of the final battles of the war began early on September 8 when Scott’s artillery began bombarding fortifications at Molino del Rey and Casa Mata in Mexico City. Cavalry and infantry charges soon followed and U.S. forces captured the positions before mid-morning. This left Chapultepec Castle, just east of Molino del Rey, as the only fortified position that remained in the city. At the crest of a 60-meter (200-foot) hill and surrounded by a huge wall, the castle included the buildings of the National Military Academy. A handful of cadets was among the more than 800 Mexican defenders at the castle. Six of the young cadets—who would come to be known as the Niños Heroes—chose to die fighting rather than surrender to the U.S. troops. After a mortar attack on the morning of September 13 failed to breach the fortification, Scott ordered his troops to storm the castle with pickaxes and crowbars. After a bloody assault, U.S. troops prevailed and raised their flag over the castle. The war was over. On September 14, Scott entered the center of the capital and the United States prepared to negotiate peace. The U.S. losses at Molino del Rey, Casa Mata, and Chapultepec included 130 killed and 703 wounded; Mexican losses are unknown, but it is estimated that nearly 3000 died in the Mexico City battles.

TREATY OF GUADALUPE HIDALGO

During the next few months negotiations continually broke down. Mexico, although decisively defeated, refused to negotiate a peace treaty. Polk became convinced that the Mexicans were stalling. He was also being pressured to acquire more territory from the vanquished Mexico. Consequently, he ordered the U.S. negotiator, Nicholas Trist, to return to the United States. Knowing that his departure would mean an end to negotiations, and possibly more problems for Mexico, Trist persevered. Eventually, on February 2, 1848, a treaty was signed at the village of Guadalupe Hidalgo, a few miles outside of Mexico City.

The Treaty of Guadalupe Hidalgo ended the war, set the southern boundary of Texas, and ceded the Mexican territories of New Mexico and California to the United States. The United States paid Mexico an indemnity of $15 million and assumed over $3 million in claims that U.S. citizens had against the Mexican government. Although Mexico lost half of its territory, it did manage to save Baja California and have it linked by land to Sonora to the east. The treaty was ratified on March 10, 1848, by the United States and on May 19, 1848, by Mexico.

CONSEQUENCES OF THE WAR

Although the United States won the war, it was less than a total victory. The U.S. forces suffered a mortality rate of 153.5 per 1000, compared to 98 per 1000 that the Union forces lost during the American Civil War (1861-1865). The high mortality rate included deaths from accidents, executions, and plagues of smallpox and syphilis. At least 12,000 U.S. lives were lost during the war, but fewer than 1800 were battle deaths.

The war’s conclusion indicated how ill-prepared Mexico had been for the conflict. Although Mexico had the numerical advantage in troops, and Mexican forces fought bravely and with resolve, U.S. forces beat them decisively in battle after battle. Mexico’s internal political battles and the refusal of the Mexican states to help finance the war effort seriously undermined Mexico’s numerical advantages. In addition, Mexican troops that were lucky to be armed with muskets were no match for trained U.S. soldiers with breech-loading rifled guns. Compared to the U.S. military, the Mexican forces were plagued by outmoded artillery, corrupt officers, and poorly trained men. Although no reliable records were kept of Mexican casualties, they outnumbered those of the U.S. forces in most major battles of the war.

Effects on the United States

The Mexican War added substantial territory to the United States. Not counting Texas, which had been annexed by the United States prior to the war, the victory increased the area of the country by approximately 66 percent. The West, including the Southwest, would become a source of basic resources and a market for industrial goods from the industrialized northeast.

In 1848 gold was discovered at Sutter’s Mill in northern California, launching the California gold rush. Silver mines were opened in Nevada, while copper began to be mined in Arizona and Utah at the turn of the century. In the mid-20th century New Mexico’s uranium mines became important for the production of atomic power. San Diego and San Francisco, blessed with two of the best natural harbors in the world, would soon host major U.S. naval facilities. These lands, plus investments in health, education, and machines, helped sustain U.S. economic growth between the American Civil War and World War I (1914-1918).

But there were hidden costs to this territorial bounty. John C. Calhoun, the seventh vice president of the United States (1825-1832), had earlier warned about territorial conquests and their potential disastrous results. The expansion of slavery in the newly acquired Mexican territories became the major constitutional and political issue that led to the Civil War.

The Mexican War was also a proving ground for many Americans who fought in the Civil War. The names of those who fought for Taylor and Scott amounted to a roll call to military greatness: William Tecumseh Sherman, Stonewall Jackson, George Meade, Franklin Pierce, Ulysses S. Grant, and Robert E. Lee, to name a few. From the U.S. Navy came David G. Farragut and Franklin Buchanan. And the inclination Americans have for electing military heroes to the presidency was exercised when Taylor, Grant, and Pierce were elected to that high office. A fourth, Jefferson Davis, who also fought in the Mexican War, was chosen president of the Confederacy.

Effects on Mexico

The Mexican heritage was more tragic. Mexicans mourned the loss of so much territory and many developed a profound distrust of U.S. citizens, as well as a fear of further “Yankee” imperialism. The chaos of war unleashed several political revolts and Native American rebellions in Mexico, including the Caste War of the Yucatán (1846-1853), in which Maya peasants overran and briefly controlled almost all of the Yucatán Peninsula.

The United States also continued to intervene in Mexican affairs, both economically and militarily. United States investors sought rights-of-way for railroads, and U.S. miners and oil men fought for Mexico’s natural resources throughout the 19th and early 20th centuries. American filibusters—military adventurers who were not part of a regular army—and U.S. soldiers and sailors intervened in Mexico several times over the next 70 years. During the Mexican Revolution (1910-1920), the United States sent 11,000 troops into the state of Chihuahua to pursue forces under the command of Pancho Villa, a Mexican revolutionary general. United States forces also occupied Mexico’s two major ports, Tampico and Veracruz, for several months in 1914.

The Mexican War and continued U.S. intervention threw a shadow over U.S.-Mexico relations until after World War II (1939-1945). Although relations between the two countries have improved, the conflict still burns brightly in Mexico’s collective memory, as demonstrated by the annual September 13 commemoration of the war and the tragic deaths of Mexico’s Niños Héroes.