the Mexican-American war is perhaps one of the United States more understudied and obvious and in many cases under appreciated conflicts in its history uh Americans don't know much about this war um perhaps it's because it's overshadowed by the American Civil War that erupted only 13 years after this war or perhaps it's due to the controversial nature of this war and the legacy of this conflict that the war has been given scant attention in secondary education institutions like high schools regardless the Mexican-American War had a profound consequence for the United States in the Antebellum era and its Legacy today remains one of controversy in fact the instigation of hostilities in this conflict actually demonstrates the controversial nature of this war it was controversial from the very beginning and that's where I want to start with this lecture I want to first start about what sparked the Mexican-American war in 1846. on March 5th 1845 a mere two days after President Polk was inaugurated the Republic of Mexico officially broke off diplomatic relations with the United States in a protest over the United States annexation of Texas now President Polk himself he was willing to go to war with Mexico in order to gain places like California and New Mexico which were kind of the far Northern regions of Mexico at this time but he didn't want to be the first one that fired a shot uh and so to precipitate a war with Mexico that would result in the acquisition of new territory which is obviously President Polk goal here he ordered a contingent of several thousand U.S soldiers under the command of General Zachary Taylor he ordered these soldiers to the north banks of the Rio Grande river which today is the border between the United States and Mexico now the Rio Grande River was some 150 miles south of another River known as the Nueces River and that Nueces River 150 miles north of where Taylor's Army was encamped this was generally considered by both sides and earlier recognized by both sides as Texas's Southern border so Polk ordering Taylor across the Nueces and and to encamp along the banks of the Rio Grande River means that Polk is sending Taylor and knowingly sending Taylor into territory that Mexico has a legitimate claim to now additionally uh Mexico recognized neither the United States annexation of Texas nor did they recognize Polk's claims that Texas's Southern border was now the Rio Grande and this then creates just an absolute recipe for disaster and just as Polk had hoped on the evening of April 25th April 25th 1846 uh Mexican troops uh attacked U.S soldiers along the banks of the Rio Grande river and ended up killing 11 American servicemen this was known as the Thornton Affair was named after the captain of the U.S Detachment Captain Thornton who led the soldiers and Thornton was actually captured himself 11 of his uh uh troops under his command were killed uh and and Thornton was actually sent back to Mexico City and imprisoned now this event the Thornton affair right this event was the pretext Polk needed to get the war that he was desperately looking for to expand the borders of the United States and so two weeks after the Thornton affair President Polk convened the United States Congress uh and requested from then a declaration of war and in his uh address to that joint session of Congress uh he spoke these words that the cup of forbearance had been exhausted even before the recent information from the frontier of the Rio Grande meaning the Thornton Affair but now after reiterating menaces Mexico has passed the boundary of the United States now I want to stop right there pay attention here Polk is essentially revising history he's saying that the Rio Grande was the border of the United States and Mexico but he knew that Mexico didn't recognize that and he himself uh previously had recognized that the Rio Grande was not the border of the United States and instead it wasn't Oasis so he's he's engaging in in a bit of revisionist History because it suits his motivation right his motives in desperately wanting to instigate a war he finished this uh sentiment by saying that Mexico had invaded U.S territory and famous words here shed American blood upon American soil that Mexico has proclaimed that hostilities have commenced and that the two nations are now at War uh and in spite of some opposition which I'm going to talk about in just a second the U.S Congress ultimately complied with President Polk's request for a declaration of war uh and it ended up authorizing the recruitment of over 50 000 soldiers uh to fill the ranks of the U.S military on May 13 1846 and of course the Mexican war had now begun now the outbreak of hostilities between the United States and Mexico really did thrill a lot of Americans uh in the South where expansionist sentiment was running high in the country during this time the war was immensely popular so many men rushed to volunteer from Southern states that many thousands of them had to even be turned away now eventually over 112 000 white servicemen served in the war and the and to reflect how popular this war was in the state in the South the state of Tennessee ended up supplying over 30 000 volunteers alone and if you know about the the state of Tennessee its nickname is the volunteer state and this was really the conflict in which Tennessee became known as that Volunteer State but in the north however the north there was less enthusiasm for this war and many of the people and congressmen in the north came to regard this conflict as quote Mr polksbore Right that this was all being driven by him and there were even Northern congressmen such as former president of the United States John Quincy Adams who was still in National politics he was serving in the House of Representatives he alleged that the entire war was a southern conspiracy to extend slavery into territories that were going to be taken from Mexico and others Stills even a young Abraham Lincoln who served one term in the U.S House of Representatives in 1845 to 1847 he stressed that Polk had actually maneuvered Mexico into attacking the United States and demanded that Polk take him down to the Rio Grande river and show him the exact spot that American blood had actually been set on American soil now the war itself while popular in the North or popular in the South and less popular in the north uh the U.S in this conflict however held many advantages and I would just want to briefly talk about some of them real quick uh for example the American population was over 20 million compared to Mexico's population of only 7 million in addition the Mexican economy was essentially bankrupt while the United States by the 1840s was very prosperous and very thriving thank you Henry Clay and the American system right and the U.S military they had better weapons the soldiers were better trained the US military had better resources and the US military had much better leadership and really the only advantage that um Mexico was going to have in this conflict is that they would be fighting on their own home turf now the Mexican-American War raged from March of 1846 all the way until April of 1848 and it was waged on four fronts now this map shows you kind of a broad overview of the entire conflict but the four principal fronts of this war were southern Texas Central Mexico the New Mexico territory and the California territory and I just want to briefly talk about California and New Mexico because the fighting in that theater of this conflict didn't last very long uh and really wasn't the principal theater of the war meaning it wasn't going to be where the war was won or lost but the fighting out in these two territories was important because it really was what Polk was after in terms of precipitating this conflict so let's talk about these territories known as California which on this map are the the light gray territory way out in the west up there in the north uh uh Western portion of this map but also the territory known as Nueva Mexico or New Mexico right which would have linked together Texas extending all the way to the Pacific and let's talk about uh California first of all the Mexican territories that President Polk coveted California was the grand prize and it was seen by most Americans including Polk but even uh others California was seen as kind of a commercial gateway to developing a trading empire with Asia and across the Pacific and it would allow the United States to open up a trade with Asia normalize relations with Asia and really allow the United States access to the rich economic markets of Asia Asia and even before the War uh President Polk had actually developed a scheme that was designed to seize uh this territory or this uh yeah this to this province or territory um called California that belonged to Mexico and the scheme that he created even before the war involved this gentleman here who was a major in the U.S army this is John C Freeman he's a very famous American military officer he's his nickname was the Trailblazer he was um uh responsible for blazing a lot of trails into the west and he was very famous around the country um but he was still part of the U.S military and Polk had recruited him uh to lead kind of a trailblazing mission into California under the pretense that Fremont and his attachment of volunteer soldiers were there to find a good route for immigrants to continue to flow into the west but the real Mission though that Polk was sending Fremont and his men on was essentially to conquer Mexican California and in June of 1846 Fremont with a force of about 60 men moved down from the Oregon Country and captured the California town of Sonoma which was at the time the largest city in northern Mexico and this is where it gets interesting because when it captured Sonoma they proclaimed it an independent republic called the Republic of California and even hoisted a flag there in Sonoma featuring a bear and a star now if you're familiar with Calif the state of California the state of California's present-day flag has a star and a bear uh and it then it's paying uh homage to this but um the bare Republic as as some people called it didn't even last a month though even though Fremont and his men were successful in in kind of uh staging a rebellion to rip away California and the reason the Republic of California or the Bear Republic didn't last very long uh was the onset of hostilities between Mexico and the United States um this is and as soon as the War Began a commander of the U.S Pacific Fleet ended up sending troops into California and onshore and ended up hoisting an American flag instead of the Bear Republic flag and by the end of July another Naval Naval Detachment arrived and occupied uh Santa Barbara which is kind of right there in central California uh and by mid-august 1846 Mexican resistance in California had pretty much been suppressed and the whole point of this you know this you see Polk trying before there's even a war to kind of precipitate a theft really in many ways of California from Mexico by uh recruiting and kind of secretly ordering John C Fremont into the area to destabilize the region and rip it away and then of course once war was declared then that gives Polk even more uh reason to send in the U.S military which he does obviously um in uh August of 18 uh or with with the onset of of uh the war and very quickly California is just overrun um by uh U.S uh Naval U.S Marines and and U.S army now what about the New Mexico territory now on this map this this New Mexico territory here is kind of this far uh region out in the left now I don't want to say too much about the New Mexico territory because there wasn't a whole lot of fighting here but um the the Conquering of the New Mexico territory was done at the under the leadership of a military Expedition commanded by a guy named General Stephen Kearney who led a small force of about 300 men into the New Mexico territory and very easily captured the city of Santa Fe which you see on this map which he did in September of 1846 and then after capturing Santa Fe which really was the key to the New Mexico territory he then marched his army in the Southern California linking up with uh those U.S naval detachments uh and Fremont's men and helped to conquer uh the rest of Southern California and capturing Los Angeles in January of 1847. so uh very quickly and very easily California and the New Mexico territory were overrun uh and taken by the United States but so now we want to turn our attention to the war then in northern Mexico or Southern Texas right right along the border of the Rio Grande and that means we need to go back and talk about Major General Zachary Taylor now from the onset of the hostilities in May of 1846 Taylor's uh General Taylor's Army ended up routing all of the military units for Mexico that existed there in South Texas and once he'd done that he then crossed the Rio Grande and seized the Mexican city of Matamoras if anybody's ever gone down to South Padre Island for uh spring break usually people will go across the border into Mata Morris this town was taken by Taylor very easily very quickly now these great these two great victories right clearing South Texas of the Mexican military and capturing the city of Matamoras these two quick victories ended up bringing a lot of national Fame and instant popularity uh to Taylor uh he was seen by a lot of people as perhaps becoming uh you know the next Andrew Jackson uh and what do we do with war heroes like Andrew Jackson well they tend to become presidents one day and so um it forced President Polk to begrudgingly then name Taylor as the overall commander in the conflict and the reason I say begrudgingly is that Taylor was a uh a vowed and very public um wig he was a supporter of the Whig party and of course polka's a Democrat and Polk's thinking that if uh Taylor becomes too famous here he might become president one day and this might cost the Democrats in the future the White House but because of Taylor's quick victories um Polk ended up begrudgingly naming him the overall commander in the theater and in the conflict uh and that meant that it was a Taylor's job to really go win the war then so beginning then in September of 1846 Taylor then moved his army Southward deeper into northern Mexico and he captured the Mexican city of Monterey which was a huge Victory and again it became it became clear that Taylor is building a lot of uh popularity and building a lot of Goodwill among the American people and he's becoming really another Andrew Jackson who might challenge the Democrats for the presidency right in the future now I'm going to go off on a bit of a Side Story here but the capture of Monterey really was a big moment in this war because it it caused the Mexican Government the Republic of Texas uh uh to really start to disintegrate and start to fall into uh to to complete collapse um and it appeared to most people was this war wouldn't even last the rest of 1846 but that's not what happened and the reason that didn't happen is I'm going to go off on a bit of a Side Story here to explain um the return of Mexico's prodigal son and that's of course Antonio Lopez de Santa Anna now the last time we saw Santa Ana he had been defeated at San Jacinto during the Texas Revolution and in exchange for his life he was forced to sign the Treaty of Alaska he returned to Mexico to ensure that Mexico would abide by the Treaty of Alaska but eventually he was overthrown and exiled by The Mexican government to the island of Cuba but with the onset of the Mexican-American war that exiled Mexican dictator Santa Anna he got word the President Polk that he could end the war if he was allowed to return from Cuba where he'd been uh you know exiled as I said since he was ousted from power in 1845. now Polk assured Santa Ana that the U.S government would pay well for any territory that they would take from Mexico and so in August Polk ended up ordering a U.S naval Detachment to arrive in Cuba and pick up Santa Ana and literally returned him to Mexico ourselves on the condition right on the condition that he was going to stay out of politics and he was going to stay out of the military and that his job then was to convince people to lay down their arms and to stop fighting the United States now of course Santa Ana lied uh and he seemed he's very soon to retook control not only of the Mexican Government but he also retook command of the Mexican Army uh and then he uh after doing so in February of 1847 he attacked General Zachary Taylor's outnumbered Army in northern Mexico at a battlefield known as Buena Vista uh now the battle itself resulted in a in a stalemate right neither side was able to destroy the other one uh even though Taylor's Army was outnumbered but the Mexican Army Santa Ana's Army it suffered horrendous casualties in this battle in fact five times as many casualties as the United States did and as a result of that General Taylor actually began planning for a counter-offensive that he believed would smash the Mexican resistance the Mexican military and lead to a quick victory but it was at that point that uh general or uh President Polk ordered Taylor to stand down and uh it ended up being the end of Zachary Taylor's War and the reason Polk did this is that after uh withstanding everything Santa Anna had and through it had been Buena Vista I mean it was pretty clear that Taylor was a big deal and the Taylor was on his way to being a war hero and represented then a a threat uh to Future Democratic political leadership because Taylor was a wig and as a result of this uh Polk was going to start shifting Manpower and shifting resources to a new overall U.S commander of the war effort and his name was Winfield Scott Winfield Scott uh what can I say about him he may not look like much but he actually was a strategic genius um to show you how well respected Winfield Scott was in military circles not just here in the United States but worldwide the Duke of Wellington which was the guy that beat Napoleon at the Battle of Waterloo once famously said that Winfield Scott was the finest military mine of his age um Winfield Scott was going to be named the new commander of the U.S war effort largely because of political reasons Taylor was winning battles he was becoming a war hero he was a Whig he threatened future Democratic political leadership in the country so Polk then uh ordered him to stand down and shifted all resources to Winfield Scott because largely because Winfield Scott well Winfield Scott was a wig and was no or a Democrat and was no threat to Polk or future political uh leadership because if he ran for office which he probably wouldn't but if he did he was a Democrat and that was what we were looking for no it's his job now to come up with a plan to win the war and as I mentioned Scott is a brilliant strategic mind when it comes to military strategy uh and his plan that he came up with was to take the the fight directly to uh uh the Mexican capital of Mexico City and the fastest way to do that was not to march from northern Mexico the fastest way to do that would be to land a sizable U.S military uh Detachment along the coast of central Mexico and March them straight towards the Mexican capital and so the target for Winfield Scott's plan was to send and land a large American Army at the coastal city of Veracruz and now the reason Veracruz was chosen by Scott was that Veracruz was the main Supply Port for Mexico City and the Mexican Army uh so taking that meant you would isolate uh um Mexico City you would isolate and eliminate the ability of the Mexican Army to be resupplied and possibly even reinforced Now The Landings at Veracruz are interesting enough because this was the first amphibious invasion in American military history the most famous of course will come in World War II on June 6 1944 that's D-Day but for the first time an American military history the United States military uh Army engaged in amphibious Invasion which means invading over land that was a technical operation there were some moments in which uh the Mexican Coastal defenses resisted for the most part this was a very easy and successful Landing in August of 1847. now from there Scott's Army needed to uh Traverse over 200 miles of rough terrain towards Mexico City and along the way Scott's Army did deliver some devastating defeats after devastating defeat against the Mexican Army at places like Sierra Gordo in April of 1847 delivered another significant defeat uh to Santa Anna's forces at the Battle of Puebla in May of 1847 and by September of 1847 Mexican military resistance had essentially been crushed there was only one last stronghold protecting the Mexican Capital it was a a large mountain just outside of Mexico City uh upon which there was a military academy built but the mountain was called the Chipotle Peck and oddly enough the Chipotle Peck is where uh the last Aztec Emperor Montezuma actually had his Palace uh and so this was a very formidable area you needed to take this High Ground in order to take Mexico City and the Battle of Japan really set up kind of the climactic end to this war um as a result of the fall of Japan uh the Mexican Government really had to just flee it scattered to the wind Santa Ana once again was forced to resign uh he he uh and formal peace negotiations began with the remnants of the Republic of Mexico's government uh in a small town known as Guadalupe Hidalgo which is just North of Mexico City but the fall of Mexico City actually occurred in September of 1847 after the fall after the battle of Chipotle Peck and it wasn't though until January of 1848 that formal negotiations with Mexico began and those negotiations took place like I said in a small town just north of Mexico City known as Guadalupe Hidalgo and uh that meant then that the treaty that officially brought an end to this war it Bears the name of the town that it was negotiated and signed in the Treaty of Guadalupe Hidalgo now I just want to talk a little bit about this treaty that this treaty is important obviously because it ended the Mexican-American War right brought an official into it um and news of not only the American capture uh of Japan but also the fall of Mexico City caused a lot of Americans especially American expansionists uh to to to really become really excited about the possibility of perhaps gobbling up all of Mexico uh for example John O'Sullivan the guy we talked about in the last lecture came up the coin phrase of manifest destiny uh he printed a headline in his paper that boldly screamed more more why not take all of Mexico but the Treaty of Guadalupe Hidalgo ultimately fell very short of people like John O'Sullivan's hopes in this Treaty of Guadalupe Hidalgo a humiliated Mexico agreed to seed over to the United States over 525 000 square miles of land uh which was nearly half of its country now that land today uh is is comprised of the the states of California Nevada Utah parts of Colorado Wyoming parts of New Mexico parts of Arizona but this land was essentially everything Mexico had from Texas to the Pacific Ocean and at the time it was dubbed the Mexican session meaning it's seeded over to the United States now in return for this land and and Polk called This Land an immense Empire uh in the Treaty of Guadalupe Hidalgo the United States agreed to pay Mexico 15 million dollars now one one thing about the legacy of this this Mexican session is that's you know Santa Ana I think famously put it best about what this what this treaty and the terms of this treaty meant for Mexico he he famously remarked that the Treaty of Guadalupe Guadalupe Hidalgo would always be a source of quote Eternal shame and bitter regret for every American for every Mexican I think he was probably right about that uh okay so that that brings us to the end of the war so let's talk briefly about the war's legacies right what what's important about this war and the war you know as I mentioned it's it's an understudied conflict of American History a lot of Americans don't know much about it but it was a very consequential one so let's talk about some of the reasons this war was important the first was that the this this war marked the first time in American history that the United States defeated and occupied another country now we kind of do that on the norm now especially in the 20th century but for the first time in American history the United States defeated and occupied another country and during this war more than 13 000 Americans died in the conflict um over 11 000 of them died of disease but this brings up one of the reasons the war is so important the war remains today the most lethal war in American military history in terms of the percentage of soldiers that were killed compared to the number of soldiers that were in the military at the time and so it's not the bloodiest war that's not what I'm saying the bloodiest war in American history the one that resulted in the most casualties was the American Civil War followed second of course by World War II but what I'm saying is that when you look at the total number of soldiers that were in the U.S military during this war and you look at the total number of then casualties uh what you find is that for every 1 000 American soldiers that fought in this war 110 of them died and that ratio right that is the highest ratio of any American conflict so that's why we say the Mexican-American war is the most lethal for a U.S serviceman to have fought in if you fought in the Mexican-American War you stood a better chance of dying in this conflict than any other war in American history now one of the other War's lasting legacies was that the war you know was charged by an increasing number of Americans over the over the next few generations and and decades it was charged and cast by a lot of Americans as very shameful uh it it the war the war became seen as a war of pure Conquest an imperialistic plundering of a neighboring nation that was directed of course by the president of the United States in order to grab more territory but grab more territory for what for slavery uh even the great Ulysses S Grant who was a lieutenant in the U.S army during the Mexican-American War but who would become obviously very famous during the American Civil War as the General in Chief of the Union Army during that conflict uh he called it you can see here that for myself I was bitterly opposed to the measure meaning the war and to this day I regard that war which resulted as one of the most unjust ever waged by a stronger Nation against the weaker one the Republic you know the United States that which was born of course out of Liberty from a colonial power had now become a continental power built upon conquest and exploitation right and for a lot of Americans in the uh for the remainder of the 19th century and even into the 20th century this was a war of great shame right um and it's important I think to remember also that there is not a single Memorial to the Mexican-American War nor is there any Grand statue celebrating the achievements of the Mexican-American War located anywhere in Washington DC which stands as unique compared to every other War we've ever fought in whether that war was controversial or not every single conflict major military conflict the United States has fought in is represented in Washington DC with some type of Memorial or some type of grand statue but not this one so I think it's important to understand that one of the lasting legacies of the war is that over time this war became seen as a a subject of great National shame now one other thing about the war's Legacy is that the war actually trained up future military leaders of the American Civil War and I just spoke you know I just referred to you uh referred to Let's assess Grant to you but he was not alone uh some of the most famous generals that commanded uh United States armies and Confederate states armies during the American Civil War they served as Junior officers right captains maybe as high as rank as Colonels they served in the Mexican-American War uh and it was in this war that they learned how to supply armies they learned how to move armies um but I also think it's important to understand that it was in this war that they perfected the tactic of using a frontal assault right and how effective a frontal assault uh of a whole bunch of soldiers charging across wide open territory out of at a finite focal point to try to break the enemy's lines it was this war that they learned how just how effective that frontal assault could be now the reason I'm telling you this is that in the American Civil War they would apply what they learned in terms of how to assault an enemy's position and how to attack your enemy they would apply what they learned in that conflict the American Civil War but the problem is in the American Civil War every Soldier was going to have much more accurate weapons and this was going to result then in the American Civil War being essentially a bloodbath but one of the other War's lasting legacies is of course it trains up the future military leaders of the American Civil War but the last and perhaps or not perhaps but definitely the most important lasting Legacy is the acquisition of the Mexican session the acquisition of this over 525 000 tract of new land new territory simply reignited a national debate here in the United States about whether or not slavery should belong in the territories of the United States now this issue of slavery's existence in the territories this this was the issue that was the first debated of course in 1820 with the Missouri controversy and it is the issue that we've reinforced a couple times already in this course that ultimately divided north and south to the point that a Civil War was possible now by the 1840s both sides were committed to their respective arguments in terms of slavery being allowed or being prohibited they were both now committed to those respective arguments as a matter of principle for the north slavery should not expand and should be barred from future territories and for the South slavery must be allowed to expand and then Congress could not restrict it and so one of the war's most lasting legacies and one of its biggest consequences for the United States is that as it turns out the Mexican-American War simply resulted in A Renewed National debate concerning the issue of slavery's expansion um and everybody recognized especially those in the north that this would likely happen this is Ralph Waldo Emerson he's a very famous American essayist very famous American transcendentalist author you've probably heard of him before but when the war first began he famously wrote in a editorial in the newspaper that the United States was going to conquer Mexico he predicted it but he also predicted that it would be as the man swallows arsenic that Mexico was going to poison us and it turns out he was right because as I mentioned the Mexican war resulted in A Renewed National debate concerning the issue of slavery's expansion to the territories of the United States and also is congress's ability to restrict it and this this reignite reignition of the national debate concerning this issue produced a very real and a very dangerous sectional crisis in the late 1840s one that threatened to rip the nation asunder and plunge it into Civil War