The Mexican-American War

This episode explores the complex history of the Mexican-American War and its lasting impact on North America. In it, we cover:

• Spanish presence in North America and the formation of the United States
• The Louisiana Purchase and its significance
• Texas independence and annexation by the U.S.
• Tensions leading to war between the U.S. and Mexico
• Key battles and military campaigns, including: 
  • The capture of Monterrey
  • The Bear Flag Revolt in California
  • The fall of Mexico City
• The Treaty of Guadalupe Hidalgo and its terms
• The Gadsden Purchase

Learn how this conflict reshaped borders and led to massive U.S. territorial gains, including California, New Mexico, and parts of several other states. Discover the complicated motivations behind the war and its long-lasting consequences for both nations.

Transcript

Damian Bacich's video recording: 0:00

Today we're going to talk about something that has had a very big impact on California and on the entire U. S. Southwest, and in fact, on Mexico as well, which is the Mexican American War. talked about the bear flag revolt in another episode, but the bear flag revolt is one episode within a larger context of the war between the U S and Mexico that took place in the mid 1840s in the middle of the 19th century, and that really reshaped. The U. S. West and Southwest and reshaped much of Mexico today. So let's, let's begin. Let's talk about it. As you likely know, the Spanish had been present in North America since the 16th century. St. Augustine is the oldest city in the U. S. that goes back to the 16th century itself. Now, many of the Spanish held territories eventually became part of the Viceroyalty of New Spain, which encompassed listen to that, which encompassed what is today Mexico. And in the northeastern parts of the North American continent, it was France and England that sort of vied for control over those territories. Now, let's go back to the independence of the Thirteen Colonies. When they broke from Great Britain, Spain suddenly found itself with territories alongside the newly formed United States. And remember, Spain had supported the colonies in the war for independence from Great Britain. So in 1795, Spain signed a treaty. with the U. S. called the Treaty of San Lorenzo, and it helped define the border between Spanish territories and U. S. territories. Now, these borders would shift over the next several years, but that was the starting point. Now, in 1803, the U. S. gained control of a major territorial asset by acquiring the Louisiana Territory from France for 15 million dollars. This deal is well known, the Louisiana Purchase. And it gave the U. S. access to lands that included what is today a whole long list of states. Arkansas, Oklahoma, Kansas, Missouri, Iowa, Nebraska, South Dakota, parts of Montana, Wyoming, Colorado, North Dakota, Minnesota, Texas, New Mexico, and Louisiana. Parts of these places. For a total of 828, 000 square miles. So with the Louisiana purchase. The US greatly increased the size of its territories and it multiplied the size of its border with the Spanish held territories, as you can imagine. So, almost two decades later, in 1819, the US signs a new treaty with Spain called the Adams Onis Treaty. Now, this agreement confirmed that Spain's claim to the territory of Texas was legitimate, but it allowed the U. S. to purchase what is today Florida. But Texas is going to be a thorny issue, as you'll see. Shortly before Mexico gained its independence from Spain. Spain granted a petition for the first group of Americans to actually settle in Texas. Until then, Americans were forbidden from occupying the Texas territory. Now, Mexico's war of independence from Spain put that petition on hold. But after Mexico achieved independence, A man named Stephen Austin, who was the son of the original American petitioner for the colony in Texas, presented a new request and he asked to bring 300 American settlers to the Texas territory. Now, the Mexican government had had difficulty in attracting settlers to the territory, partially due to its difficulties with the Comanche, right? And so it approved the petition. Mexico allowed Stephen Austin and his settlers to enter Texas on certain conditions that they set out. One, they had to be of good moral character. They had to practice Catholicism, which was part of the new, Mexican Republic and follow the laws of Mexico. Now, although Austin's permission was unique at the time, Mexico eventually passed a colonization law in 1825 that allowed thousands of foreigners to settle in Texas. By 1835, there were 20, 000 Americans, including Cherokee Indians, in Texas. And that was four times the size of the native born Mexican population, which is about 5, 000. So they overwhelmed the population of people already living there. Although Mexico initially saw American immigrants as a way to shore up its control of this difficult territory, It eventually began to have second thoughts and to doubt their allegiance. They began to view the new immigrants with suspicion. Texans in turn became resentful at their own small amount of representation in Mexican politics. And these tensions reached a tipping point eventually. And that was when General Antonio Lopez de Santana took office as president of Mexico in 1834. Santana was a centralizer and he soon revoked the constitution. He set about decentralizing governmental authority in Mexico, excuse me, centralizing it, in fact, concentrating it in Mexico City and thereby reducing the autonomy of the individual states, which up until that time had sort of steered their own vote. Now, as you can imagine, this caused a great amount of unrest in some of the territories, particularly Texas. And in September of 1835, Texans begin a war of secession, that is to break away from Mexico. In November of that year, a group met in San Felipe de Austin and established a provisional state government. Now, they fought for several months with Santana's army, and on March 2nd of 1836, Texas declared its independence from Mexico. The Mexican army fought the insurgents for several weeks, including at the famous Battle of the Alamo, which we all know about. And that's where Santana's troops actually defeated a group of Texas fighters who were holed up in the old mission. And we all know the phrase, remember the Alamo because it was a famous defeat, but that loss was eventually turned into a victory. Sam Houston's Texas ultimately won the day. They lost the battle, but they won the war. And on April 21st, General Santana, who had been captured, signed the Treaty of Belasco, which recognized Texas's independence. Nevertheless, Santana's capitulation was not the final word. The Mexican Congress refused to ratify the treaty since they considered that the general was a prisoner of war. And so it was an illegal or coerced signing, right? But the U S had a different view on it. The U S recognized Texas as an independent Republic. on March 3rd of 1837. Mexico would not recognize Texas as independent and it couldn't, however, do anything about it. There were struggles going on in Mexico and the government lacked money and so there was not much that they could do at that moment to try and retake Texas. In the meantime, the U. S. had an aspiration to control the North American continent and it also wanted to keep out its great rivals who it saw as France and Great Britain. Of course, this put it on a collision course. For sure with Mexico. And the first inklings of that came a few years later with an interesting episode in 1842. So at that time, the commander of the U S Pacific squadron, the Naval squadron, a man named Thomas App Catesby Jones received news that the French had sailed from the coast of South America and were on their way, possibly to California's French Naval vessels. He also learned that British ships might be en route to California. So armed with this news and a message from the U. S. Consul at Mazatlan, Mexico, who implied that war with Mexico over Texas was actually imminent, Commodore Jones set sail for Alta California. Now keep in mind he had received no orders or official confirmation about a war. But he believed with the news he had, it would be cowardly not to strike. And so on October 18th of 1842, Commodore Jones sailed his squadron into Monterey Bay and anchored his ships right there. Keeping in mind that Monterey was the capital of Mexican California. The following day, he sent officers ashore to demand the surrender of the governor Juan B. Alvarado and the military detachment at the Monterey Presidio. Now, the Presidio was defended by approximately 50 soldiers and many of them really had no military instruction at all. It was not a, it was not a crack unit. Jones, on the other hand, had 800 men and 80 cannons aboard, a total of 80 cannons aboard his warships. So, with Thomas Larkin, who was the U. S. consul, acting as an interpreter, he had the Mexican officials sign surrender documents, because they were sort of over a barrel. But despite the surrender, Larkin, the U. S. consul, kept insisting with Commodore Jones that there were No news of any sort of war having broken out. And in fact, the Mexican documents that he sees during the occupation also showed no evidence of war. Eventually the Commodore himself became convinced that perhaps this was all a big mistake. So, on October 21st, he actually ordered the U. S. flag lowered, the Mexican flag raised again, and he apologized for his actions. In fact, everybody had a big dinner afterwards and seemed to got along well. He also sent word to the new Mexican governor, who had been appointed in the meantime, Manuel Michelle Torena, about what had happened, and Michelle Torena had ordered a All the military commanders in Sonoma, Santa Barbara, and Los Angeles to organize a resistance against the Americans. And of course this put that whole thing on ice. Now, although the incident at Monterey ended peacefully, they were sort of a portent of things to come. And over the next few years, the two countries wound up being pushed closer and closer to war. And Texas. would be the spark. In 1843, after years of continuing disputes in Texas between, you know, Mexico and the Texas colonists, Great Britain and France actually helped arrange a truce between Texas and Mexico. Now this sort of alarmed U. S. lawmakers who worried about Britain and France meddling in North America and what their interests might be in Mexico and in Mexico's Northwest Territories. So, in February of 1845, the U. S. Congress passed a joint resolution calling for the annexation of Texas. In June of that year, the Texas Convention of Representatives also approved Texas annexation to the U. S. And President James K. Polk of the United States therefore ordered U. S. troops into Texas. Now, he also sent warships to the Gulf of Mexico and strengthened naval forces in the Pacific. In doing so, Polk, what he was doing was supporting the Texans claims in its boundary, in their boundary dispute with Mexico. So Texas claimed that the southern border of Texas should be at the Rio Grande River, which in Mexico is known as the Rio Bravo. And Mexico claimed that it should be further north at the Nueces River. Now, in a parallel move, Polk actually sent a representative to Mexico to try and, by, to try and avert a war by negotiating a purchase. of California and New Mexico. Well, it didn't really avert a war, but he tried to buy California, New Mexico. Now, the Mexican government at the time was full of debts, but it refused the offer, as you can imagine. In October of 1845, the people of Texas ratified the U. S. annexation. And by the end of December, Texas was officially part of the US President. Polk then ordered US troops to cross the Noesis River and deploy south between the NOIs and the Rio Grande. With Texas now considered part of the US and with this move into the no man's land, tensions could only rise. In April of 1846, the US Navy blockaded the Rio Grande River and Mexican General. Their Mexican general Pedro Ampia therefore ordered the US Commander to withdraw his forces north of the nos. When the commander refused Mexico, declared a defensive war on the United States and its forces attacked US troops. between the Nueces and the Rio Grande. This was really the beginning of the war. In response, on May 13th, the U. S. Congress declared officially war on Mexico. Now, with the U. S. at war with Mexico over Texas, Polk wanted to sort of tidy up some other difficulties that he had been dealing with and be able to focus on winning that war. He therefore moved to settle what had been a long simmering dispute with Great Britain over the Oregon Territory, the area, you know, along the Canadian border, along the Pacific side and the Northwestern coast, right? And so In June of that year of 1846, the U. S. and Great Britain signed an agreement which actually granted the U. S. control of everything below the 49th parallel. So now, the Oregon issue was settled, right, and the U. S. was free to focus on the war with Mexico. U. S. forces now started focusing on Mexico's far northern territories, right, which is today the U. S. Southwest. In August, U. S. military forces led by Colonel Stephen Watts Kearney captured Santa Fe, the capital of New Mexico. U. After the governor of the territory, Manuel Armijo, dissolved his army and left for Chihuahua. So there wasn't, even though there were battles, there was hostile, there was combat in New Mexico, let's say, it wasn't a huge theater. The next major objective for the army, therefore, was to capture the capital of northeastern Mexico in the Rio Grande area. which was the fortified city of Monterrey, right? So on September 25th, after fierce fighting and major artillery bombardments, the U. S. actually captured the city. And by the end of 1846, the U. S. had control of all of the northeastern territories of Mexico. Now, in January of 1846, let's talk about California, U. S. Army Captain John C. Fremont arrived in the Salinas Valley of California on what he described as a scientific expedition. While there, he met in Monterey with U. S. Consul and now confidential agent Thomas Larkin, the same Larkin who had been in on the whole situation in Monterey in 1842. Now, they talked about the hostilities over Texas and plans for also Alta California. As you can imagine, Fremont's presence in the capital of Mexican California started to raise eyebrows. And Mexican military commander of the area, Jose Castro, who was a Californio, born in the territory, was, understandably suspicious of a U. S. Army officer wandering about California with an armed escort. So he soon ordered Fremont to leave. Now, rather than follow Castro's orders and leave, excuse me, Fremont and his men set up an encampment on Gabilan Peak above the Salinas Valley, which is now known as Fremont Peak. And raise the American flag for all to see. Now this armed encampment remained in the area until March of 1846, and then moved north to the Oregon Territory. On May 8th and 9th of that year, He met with a man named Archibald Gillespie, a U. S. Marine Corps Lieutenant, who had also interviewed California clandestinely and who was trying to catch up with Fremont to talk to him about the hostilities that were brewing. By the end of May, Fremont returned to Alta California, accompanied by his men and a detachment of Delaware Indians who were allied with the U. S. He then lent his support to the group of American immigrants who were around, in and around the Pueblo of Sonoma, who also had their own plot to break from Mexico, just as Texas had. And the uprising, the Bear Flag Revolt, which we talked about earlier, took place on June 14th. And briefly, With Fremont support, the Bear Flaggers, or the Olsos, as they were known in Spanish, raised the homemade grizzly bear flag over the town of Sonoma, took General Mariano Guadalupe Vallejo, prisoner, and brought him to John Sutter's fort. and along the Sacramento River. The flag that they made would eventually become the basis for the California state flag, which was officially adopted in 1911. On July 7th now, and this is where things get really interesting, U. S. Naval Commodore John Drake Sloat arrived off the coast of Monterey. There, he ordered the Marines ashore to raise the American flag over Monterey. Five days later, he did the same thing in San Francisco. In the meantime, Fremont incorporated the Bear Flaggers, the Alsos, into a newly formed California battalion of the U. S. Army, and he made his way to Monterey with them. Along the way, though, the violence of his troops and irregulars enraged both Californians and Americans who accused them of wanton murder. Fremont was accompanied by the famous mountain man and scout Kit Carson, and with him, the troops bordered ships bound for San Diego. And there, the idea was to reinforce the campaign that was actually taking place in Southern California at the same time. Now, by early August, U. S. troops, so let's talk about Southern California. U. S. troops were in control of the Pueblo of Los Angeles, and the governor at the time, Pio Pico, had fled to Baja California. vowing to return. But the city's inhabitants who remained were chafing under the occupation by a U. S. military and they eventually rose up and forced Marine Captain Gillespie, who was now a cap, had been lieutenant, now a captain, and was now the U. S. commander there to flee the city. On December 6th, a force of Californians actually defeated U. S. troops under Stephen Watts Kearney, who had been promoted to general, at the Battle of San Pascual, which is in today's San Diego County. And a side note, there's a San Pascual Battlefield State Historic Park, but it's been closed since COVID. I hope they can reopen it at some point. In any case, in January, the U. S. mounted a full blown invasion of the Pueblo of Los Angeles with soldiers, marines, sailors, and artillery. The invasion successfully overwhelmed the Californios, who were always a small force anyway. And on January 10th of 1847, LA, Los Angeles, fell to the U. S. at the Battle of La Mesa. The Californios surrendered officially three days later at a place called Campo de Cahuenga. Which is today's Universal City. The agreement that ended the fighting became known as the Treaty of Cahuenga, or to the Americans, the Capitulation of Cahuenga. So, with Mexico, now Mexico's northwestern territories are under U. S. control. So, President Polk decides to now aim for the capital of Mexico, Mexico City. And so, US troops landed at Veracruz and retraced the route traveled by Hernan Cortes in 1519. And this landing takes place on March 9th of 1847. Veracruz takes three weeks to fall. And on March 29th The city falls after days of bombardment. May 15th, 4, 000 U. S. troops capture the city of Puebla after defeating Mexican forces at the Battle of Cerro Gordo on April 18th. And after the fall of Puebla, the U. S. begins its march toward Mexico City. Battling Santana's troops all along the way. After Santana rejects a truce offered by American Major General, American Major General Winfield Scott, US forces then take up positions outside of Mexico City to lay siege to it. They soon began bombarding the historic Chapultepec castle. Which is located on a hill overlooking the city. The castle, the Chapultepec castle, actually housed the military academy for the Mexican army. And filled, so it was filled with soldiers and young cadets. who refused to surrender. So the next morning, U. S. soldiers stormed the castle, and they eventually take it. And in fact, you have the famous Niños Héroes, the child heroes of this engagement. Now, U. S. forces then moved to the gates of the city, where fighting with Mexican regular troops broke out. The battle spread throughout the city and lasted until nightfall. After civilian officials in Mexico City convinced Santana to withdraw his troops to avoid more bloodshed, there was nothing to do, but to allow American forces to take control of the Capitol. The Mexican government, so then, relocates its headquarters to Querétaro. Which is about 135 miles away from Mexico city. And on September 16th, 1847, which is actually the commemoration of Mexican independence, General Antonio Lopez de Santana announces he's stepping down. He soon left the country for exile in Kingston, Jamaica. And the United States then goes, the United States Army, I should say, then goes from being an invasion force to an army of occupation. So troops remained in Mexico City from September 14th of 1847 to June 12th of 1848, almost a year. And with the effective surrender of Mexican forces, The two governments start negotiating a treaty. Okay. However, back in the U S legislators were divided about how to proceed. So in Congress, there even arose a movement to annex the whole country. Right. This movement came to be known as the all Mexico movement. Obviously that didn't happen. Right. Okay. But still, in less than a month, a treaty between the two nations was signed. On February 2nd, representatives of the two nations met at a place called Villa de Guadalupe Hidalgo, which is now a neighborhood in Mexico City. And the agreement, the treaty, came to be known as, take a guess, the Treaty of Guadalupe Hidalgo. And that is the treaty that governed, supposed to be governing people in the territories seized from Mexico. So in it, the U. S. committed to compensate Mexico 15 million and to pay off the claims of U. S. citizens against Mexico up to a total of 5 million. So the U. S. is in it for 20 million. The U. S. Senate then ratified the treaty on March 10th of 1848. So what did the treaty set out? Well, it set the Texas border at the Rio Grande River. It conceded Alta California to the United States, which, by the way, included much of today's Arizona, as well as Nevada, Utah, and parts of Colorado and New Mexico. Now Mexican, now think about this, Mexican citizens had the right to remain where they were or to go to Mexico, to go to the newly, on the other side of the newly formed Mexican border. Those who chose to stay in the U. S. territory could continue on as Mexican citizens, or they could automatically receive American citizenship. They were also to retain all their rights and property. Nevertheless, although a peace treaty had been signed, over the next several years, tensions continued to simmer between the U. S. and Mexico because there was a dispute over territories in Mexico's Mesilla Valley, which later became parts of Arizona, the states of Arizona and New Mexico. The territories and later the states of Arizona and New Mexico. In December of 1853, the two countries signed a new deal which ceded the territory, this disputed territory, to the U. S. for 10 million dollars. The agreement was known as the Gadsden Purchase and it was ratified in 1854 and it granted the U. S. the land it needed. To finish building the Transcontinental Railroad.

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