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United States–Mexico Border

United States-Mexico Border

The United States-Mexico borderlands constitute the region where the United States and Latin America have interacted most intensely. Over time the nature of that relationship has involved both conflict and interdependence.


International borders are likely to be the scene of conflict because of such basic factors as vague territorial limits, unclear title to natural resources, ethnic rivalries, and restrictions placed on the movement of goods and people across the political line. Where frontier conditions exist, lawlessness is frequently a problem. In remote, sparsely populated areas, the restraints that govern residents of settled regions tend to be weak. Underfinanced local governments struggle to exert their ineffective authority over wide expanses of territory. The international line itself represents a powerful escape valve for fugitives from the law. Bigots and racists tend to take advantage of prejudices that run strong in small communities. In short, at the outer edges of nations, oppressors and transgressors of all shades enjoy shields from punishment not available in the heartland. In the history of the U.S.-Mexico border, these and other problems have complicated the relations between the two countries, making life difficult for the area's residents during periods of heightened animosity.

The Texas rebellion (1836) and the Mexican-American War (1846–1848) exemplified the border-focused conflict in the first half of the nineteenth century. Disorder and bloodshed continued after the demarcation of the new political line following the signing of the Treaty of Guadalupe Hidalgo (1848) and the Gadsden Purchase (1853).

One of the greatest sources of strife in the nineteenth century was the recurring transboun-dary Indian raids. A provision in the Guadalupe Hidalgo Treaty bound the United States to prevent Indian incursions into Mexico. Unable or unwilling to carry out this provision, the United States abrogated the treaty in 1853 with the completion of the Gadsden Purchase. Nevertheless, an understanding remained that each country assumed responsibility for preventing indigenous tribes from using the respective national territories as springboards for transborder forays. As the depredations into the Mexican borderland settlements continued year after year, Mexico bitterly protested the alleged U.S. indifference to the problem.

Problems with slave hunters, smugglers, robbers, cattle thieves, and desperate characters of all shades further increased the tension between the two countries. The general lawlessness characteristic of many European Americans living along the border led to the violation of Mexico's territorial integrity, including repeated filibustering expeditions into several northern states. Mexican border residents suffered plunder, pillage, and murder at the hands of desperadoes and adventurers. Among the many foreigners who sought to establish empires or colonies on Mexican soil, none is better known than William Walker, whose invasion of Baja California and Sonora in 1853 was short-lived. The U.S. frontier, particularly in Texas, also endured depredations from criminal elements who used the Mexican borderlands as a base of operations. Cattle rustling and smuggling particularly disturbed Texans. Retaliatory raids fomented by European American mistreatment of Mexicans, such as Juan Nepomuceno Cortina's exploits in the Brownsville-Matamoros region in the 1850s, fanned racial hatred even more.

Each country accused the other of failing to suppress such disorders, and by the late 1870s relations became strained almost to the breaking point. With the advent of the railroads in the 1880s and the subsequent influx of more stable elements and influences, however, marauding and raiding activities declined. During the next three decades the frontier experienced relative peace and order.

The Mexican Revolution of 1910 introduced a new era of instability when Mexican bandits and revolutionaries raised havoc in the Texas and New Mexico borderlands. For a time, residents in the U.S. border states lived in fear that extremists from the neighboring country, aided by militant Mexican Americans, would attempt to retake lands lost by Mexico in the nineteenth century. The tensions of the decade occasioned several crossings of U.S. troops into Mexican territory, including the unsuccessful chase of Pancho Villa by General John J. Pershing in 1916–1917. By the middle of the decade, war between the two countries seemed likely; but the crisis abated as the violent phase of the revolution waned and the United States turned its attention to World War I. Thereafter confrontation over borderland violence ceased as a major diplomatic issue between the two nations.

Pinpointing the precise location of the border became a highly volatile problem in the first years of binational contact, and remained a sore point until the 1960s. Disagreement over whether the Rio Grande or the Nueces River constituted the actual boundary between Texas and Mexico became the immediate cause of the U.S.-Mexico War. Acrimony continued over this issue because of the inexact identification of the new line of demarcation in the Treaty of Guadalupe Hidalgo. Errors in surveying caused the Mesilla Valley in present-day New Mexico to become a hotly disputed territory until Antonio López de Santa Anna gave in to U.S. pressure and sold the area as part of the Gadsden Purchase in 1853.

Changes in the course of the unpredictable and often violent Rio Grande have resulted in boundary disputes as well. The best known of such controversies began in El Paso, Texas/Paso del Norte (present-day Ciudad Juarez, Chihuahua) in 1864, when the river suddenly turned southward, resulting in the U.S. annexation of a section of Mexican land known as El Chamizal. Mexicans attempted for decades to regain the lost land through arbitration, escalating their efforts during the era of Porfirio Díaz, but the United States would not accept Mexico's claim to the Chamizal. In 1911 the U.S. government refused to abide by a decision favorable to Mexico rendered by the International Boundary Commission. After decades of stalemate, the two governments finally resolved the issue in 1963 by agreeing to terms essentially worked out in the 1911 arbitration. With the signing in 1970 of a treaty to resolve remaining and future boundary differences, the possibility of serious conflict over border delimitation diminished considerably.

Another problem that has caused bitter controversy pertains to the distribution and use of the water in the rivers that form part of the border region: the Rio Grande, the Colorado River, and the Tijuana River. A century of controversy began in the 1870s when irrigation development reached the U.S. borderlands. Decades of negotiation resulted in two treaties, one in 1906 and one in 1944, that established terms for the division of waters. Yet both treaties contained serious flaws. The 1906 pact divided the water of the upper Rio Grande (from its source to Fort Quitman, Texas) but left the apportionment of the waters of the lower Rio Grande, the Colorado, and the Tijuana unresolved. These omissions triggered a generation of agitation. Matters calmed down somewhat in 1944 with the ratification of the second treaty, but the new pact (covering the waters of the Rio Grande below Fort Quitman and of the Colorado and Tijuana Rivers) not only overestimated stream flow but also contained ambiguous provisions regarding drought and water quality, thus leaving both Mexican and U.S. farmers dissatisfied with the amount and type of water available for their irrigation projects. These and other problems diminished the effectiveness of the treaty. The excessive salt content of the Colorado River water reaching Mexico, which after 1961 began causing serious damage to thousands of acres of Mexican land, became a particularly troublesome issue. The two countries did not resolve this problem until 1973, when a new binational pact provided for the reduction of salinity through the construction by the United States of a desalting plant, the cooperative rehabilitation and improvement of the impaired lands, and the waiver of previous Mexican claims. Although desalination has lessened the problem, saline water has not been totally eliminated. Further, the reduced flow resulting from upstream damming and diversion has practically ruined the once thriving ecosystem of the Colorado River delta.

A prolonged drought from 1992 to 2002 led to severe water shortages and sparked a bitter quarrel between Texas farmers and the Mexican government. The farmers accused Mexico of hoarding water from tributaries that feed into the Rio Grande and pressed the U.S. government to force compliance regarding treaty-mandated water deliveries. With abatement of the drought, Mexico began paying its water debt. By 2005 a binational agreement settled the dispute, although Texans remained bitter over lack of compensation for crop losses.


After the delimitation of the boundary in the mid-nineteenth century, new settlements emerged and existing ones grew as migrants arrived from the interiors of Mexico and the United States. A symbiotic relationship evolved between one side of the border and the other, with the United States assuming the role of dominant partner. One immediate effect of the establishment of the new boundary in 1848 was to convert Mexican frontier settlements at the Rio Grande into satellites of the U.S. economy. The competition provided by U.S. merchants who moved into the region devastated many Mexican businesspeople who had no access to capital and manufactured goods, both of which were more readily available to their counterparts across the line. For ordinary fronterizos, the major effect of the new border was a higher cost of living, for after 1848 tariffs had to be paid on foreign commodities. As a result of economic dislocation, scores of Mexicans migrated to the United States, where living conditions were more favorable.

The Mexican government provided some relief to the border communities by allowing a zona libre (free zone) to function in certain border areas beginning in the late 1850s. Under the zona libre, Mexican border residents could import foreign products without having to pay the normal duties. This helped to stimulate the economy of the border towns, but the external dependence increased. In 1885 the Porfirio Díaz regime recognized the unique conditions at the frontier and extended the zona libre along the length of the border. Local trade flourished, ushering in prosperity unseen in previous eras. Yet dependence on the U.S. economy grew deeper because the commercial stimulus was being driven from abroad. Then in 1905, following protests from U.S. merchants hurt by the diversion of commerce to the Mexican side, and pressures from Mexican businesspeople and industrialists in the interior who resented the preferential treatment given to borderlanders, the Mexican government eliminated the zona libre. In the decades that followed, borderlanders continuously petitioned for the return of free trade but succeeded only in persuading Mexico City to allow duty-free importation at selected parts of the border.

Meanwhile, U.S. capitalists penetrated the economies of the northern Mexican states, in particular Chihuahua and Sonora. By the 1880s U.S. companies had built railroads along important routes that connected central Mexico with El Norte (The North) and with the United States. As the railroads reached rich mining districts and productive agricultural and ranching areas, they came to symbolize U.S. dominance, for they facilitated the export of precious metals and raw materials to the United States. The railroads also transported Mexican workers to U.S. work sites throughout the borderlands. As owners of Mexican mines, oil fields, farms, ranches, and sundry industries, U.S. citizens exerted disproportionate influence in Mexico, engendering resentment among Mexicans. That resentment played a pivotal role in the turmoil that gripped Mexico in the early years of the twentieth century, an unrest that assumed nationwide proportions by 1910, eventually exploding into a full-scale revolution.

After the revolution, Mexico began the process of political, economic, and social reconstruction, slowly eliminating the conditions that had precipitated internal instability. Modernization and sustained economic growth became strongly institutionalized in the northern states and in the U.S. Southwest. Thus a closer relationship evolved between the two sides of the boundary, shaping the region in ways that differed considerably from earlier periods, when isolation, underdevelopment, and disorder were commonplace.

In 1919 the Volstead Act made it illegal to produce or sell alcohol in the United States, causing the Mexican border cities to become magnets for manufacturers of liquor and operators of bars, nightclubs, casinos, and related establishments. During Prohibition, many U.S. entrepreneurs joined Mexican businesspeople in catering to the demands of a large U.S. clientele eager for alcoholic beverages and entertainment not readily available in the United States. Consequently, cities such as Ciudad Juárez and Tijuana acquired reputations as centers of vice and moral abandon.

The onset of the Great Depression temporarily halted the trend toward institutionalized interdependence along the border. Massive unemployment created strong pressures to rid the United States of foreign workers, with Mexicans targeted as a primary group for deportation and "repatriation." Thus in the 1930s between half a million and one million Mexicans, many of them U.S. citizens, left the United States involuntarily and as repatriates. For the border communities, the returnees presented special challenges because most of them needed basic assistance and transportation to the interior.

The greatest socioeconomic changes in the borderlands have taken place since World War II. At that time the U.S. government began to invest enormous amounts of capital throughout the Southwest in military installations, defense-related industries, and infrastructure projects. The infusion of these external funds stimulated the entire economy, helping to convert the U.S. border region into one of the most dynamic areas in the country. As an extension of the U.S. Southwest, northern Mexico benefited considerably from these trends, as well as from the industrialization policies promoted from Mexico City during the same period. By the late twentieth century El Norte emerged as one of the most modern and prosperous regions within the Mexican republic.

Both sides of the border sported a greatly expanded economy capable of sustaining substantially larger populations. Traditional extractive and agricultural industries were pushed into the background, replaced by manufacturing and high-tech industries that relied heavily on government spending. New forms of industrialization emerged with the establishment of maquiladoras, foreign-owned assembly plants situated on the Mexican side of the border. Urban centers throughout the binational borderlands assumed a new look, evolving from isolated, underdeveloped towns into modern, vibrant metropolises. Some cities achieved national prominence within their respective nations. At the border, communities such as Ciudad Juárez-El Paso and Tijuana-San Diego became highly integrated binational centers of great significance for both nation-states.

The post-World War II economic expansion spurred impressive population growth throughout the borderlands. By 2000, 17 million people lived in the Mexican border states, compared with 8 million three decades earlier; north of the boundary, the population of the U.S. border states rose from 34 million to 65 million. Thus by 2000 the combined population of the binational borderlands was 82 million.


Since the 1990s issues related to trade, migration, and drugs have dominated the U.S.-Mexico border relationship. The North American Free Trade Agreement (NAFTA), enacted in 1994, has significantly increased binational economic interaction, bringing benefits to many consumers and select merchants, industrialists, and workers. However, Mexicans situated in sectors that find it difficult to compete with the U.S. economy have experienced significant setbacks, while U.S. residents that cannot match the cheap-labor industries in Mexico have likewise been hurt. Drug traffickers have capitalized on the NAFTA-driven dramatic rise in truck traffic across the border to smuggle greater amounts of their illegal products into the United States. In addition, NAFTA has worsened migration problems on the border as a result of increased movement to the United States by Mexicans from rural areas in the interior that were devastated by importation of cheap U.S. foodstuffs.

NAFTA's impact on migration is clearly a contributor to the escalation of binational friction over this issue since the 1990s. Yet the troublesome issue of cross-border migration has complex and deep roots that precede NAFTA by many decades. Certain border areas have experienced severe stress as would-be undocumented migrants have been driven from the large border cities by U.S. blockades and forced to cross into the United States by way of remote and dangerous deserts and mountain areas. As a result, more than 3,000 people perished from exposure to the elements between 1993 and 2005. During that period the anti-immigrant sentiment grew substantially in the United States, triggering a wave of anti-immigrant state and local laws as well as pressure on the federal government to pass national restrictive legislation. In 2006 the U.S. Congress engaged in acrimonious debate over the immigration issue, especially in light of concerns that arose after September 11, 2001, about securing the border from foreign terrorists.

Drug trafficking, which also reflects the reality of a porous border and triggers security concerns, has generated many disputes between the two countries. Yet it is the Mexican border communities that have felt the sharpest effects of the drug trade. Cities such as Tijuana, Ciudad Juárez, and Nuevo Laredo have turned into battlegrounds as drug cartels have fought each other as well as law enforcement for the privilege of conducting their nefarious business without obstruction. Protracted violence, crime, and corruption have wreaked havoc on the citizenry. It appears that for years to come the drug problem will remain one of the major challenges confronting the border.

See alsoChamizal Conflict; Díaz, Porfirio; Gadsden Purchase; Guadalupe Hidalgo, Treaty of (1848); Mexico, Wars and Revolutions: Mexican-American War; North American Free Trade Agreement; Pershing Expedition; Santa Anna, Antonio López de; Villa, Francisco "Pancho"; Walker, William.


Arreola, Daniel D., and James R. Curtis. The Mexican Border Cities: Landscape Anatomy and Place Personality. Tucson: University of Arizona Press, 1993.

Fernández, Raul A. The United States-Mexico Border: A Politico-Economic Profile. Notre Dame, IN: University of Notre Dame Press, 1977.

Ganster, Paul, and David E. Lorey. The U.S.-Mexican Border into the Twenty-First Century. 2nd ed. New York: Rowman & Littlefield, 2008.

Hall, Linda B., and Don M. Coerver. Revolution on the Border: The United States and Mexico, 1910–1920. Albuquerque: University of New Mexico Press, 1988.

Herzog, Lawrence A. Where North Meets South: Cities, Space, and Politics on the U.S.-Mexico Border. Austin: Center for Mexican American Studies, University of Texas at Austin, 1990.

Martínez, Oscar J. Border People: Life and Society in the U.S.-Mexico Borderlands. Tucson: University of Arizona Press, 1994.

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Rippy, J. Fred. The United States and Mexico. New York: Knopf, 1926.

                                     Oscar J. MartÍnez

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