The Mexican-American War


The Mexican-American War

Mexico and the United States are two countries that have rarely been at war with their immediate land neighbors, and for good reason: they don’t have very many. However, their geographical proximity has caused a certain amount of unrest, which continues to this day (just think of the recent U.S. presidential election debates). Here, we look back at the most famous episode in the relationship between the two countries: the conflict of 1846-1848, known to some as the Mexican War and to others as the War of the United States Invasion!




Texas’s status was at the root of the conflict. Initially a Mexican territory, it had declared its independence in 1836 and was not recognized by Mexico, which disputed its borders. In 1845, the ever-expanding United States annexed the young Republic of Texas, whose population consisted mainly of Anglo-American settlers.


On April 24, 1846, a troop of Mexican horsemen attacked an American army patrol in the part of Texas that was claimed by both countries. The incident, dubbed the “Thornton Affair” after the captain of the massacred patrol (only one survived), triggered the outbreak of hostilities.


Several fronts


The motives that prompted the United States, led by President James Polk, to create the conditions for war, and then to declare it, reached beyond Texas to include California, which was then a Mexican state.


The US army quickly invaded its neighbor's territory on two different fronts, one to the west and the other along the Rio Grande. At the same time, Americans in California, who were worried about their position in this nascent war, revolted against the Mexicans, declaring the Republic of California’s independence on June 15, 1846. This didn’t even last a year but set a precedent that a few years later would lead it to definitively secede from Mexico and join the United States.


Many battles punctuated this two-year conflict, including those of Monterrey, Buena Vista, and Contreras. But Mexico was still a young and politically unstable country. Although US independence was also less than a century old, it was more structured and in better shape economically. After a war that was exhausting for both sides but dominated by the United States, General Santa Anna’s troops declared defeat on September 14, 1847, and surrendered to the Americans in Mexico City.


The war’s consequences


A peace treaty signed in 1848 marked the end of the Mexican-American War. Mexico had lost half its territory to its adversary, including California, where gold would be discovered a few years later. But the surrendered lands would forever bear an undeniable Mexican influence. Even today, many towns in Texas and California have Mexican names, and Spanish is sometimes more commonly spoken than English.