The Mexican American War

The Mexican-American War

Manifest Destiny or a War of North American Aggression—Or Something Else?

In the United States, the Mexican-American War is half-forgotten and yet seminal, driven by expansionism and a sense of Anglo-Saxon superiority over all other peoples.  Whether to go to war was a deeply divisive issue, and it resulted in what from the perspective of U.S. combatants can best described as a “short, offhand, killing affair.”[1]  Mexicans have quite naturally taken a different view of the war that casually sheared away more than half its territory.  The North American Invasion was what José María Roa Bárcena called the war in his seminal work published in 1902—a term that is nearly universally used by Mexicans when speaking of the war.  Mexicans have also long called it the War of North American Aggression—an act of aggression decades in the planning and making, in eyes of many Mexicans.[2]

Hostilities commenced in April and May of 1846, in the brush and mesquite along the northern bank of the Rio Grande, some nine months after Billy Gogan’s adventures in Gotham ended in the Great Fire of New York of July 19, 1845.[3]  The war became the great event in U.S. history of the 1840’s and has traditionally served in the eyes of many U.S. commentators as a dress rehearsal for the holocaust of Civil War that was to consume the country hardly more than a decade and a half later.  In Mexico, the repercussions were felt for decades.  They culminated first in civil war in the 1850’s and victory for the liberals and Benito Juarez over the conservatives, who thought the liberals unfit to rule blamed the liberals for the War of North American Aggression and the resulting loss of territory and national pride.  The conservatives had their revenge in 1862, when they aided and abetted an invasion by the French in 1862, which resulted in a Hapsburg emperor, Maximilian, ruling over Mexico until, in 1867, the French having withdrawn, Benito Juarez once more prevailed and Maximilian was shot by a Mexican army firing squad.

So why did this war, neglected in U.S. memory and yet so pivotal for the future, come about?  What possibly could have driven the U.S., a country with an army of somewhat less than 5,500 professional soldiers scattered in company-sized (or smaller) detachments over half a continent, to invade Mexico, a country whose land area was likely greater than its own?[4]  Not surprisingly, the viewpoints from north and south of the Rio Grande have differed over the years, and continue to differ to this day.

From the American Perspective—Why the Drumbeat for War

First and foremost, the issue of what to do about Texas drove U.S. actions in the period of 1844-1846.  Texas had been an independent republic since 1836, when primarily white, U.S.-born rebels succeeded in defeating the Mexican army led by Santa Anna at the Battle of San Jacinto, an event revered to this day in Texan history.  Santa Anna was captured, and as the price for his freedom, he agreed as President of Mexico to grant Texas its independence and fixed its southern border at the Rio Grande, even though the historical border of the province had traditionally been along the Nueces, 130 miles to the north.

Santa Anna was promptly overthrown as president, and his peace treaty granting Texas its independence and fixing the border was repudiated.  Texian (as they were referred to in those days) independence thus continued to be at issue for the next decade, until she was admitted into the Union.  In 1842, an expedition led by General Adrian Woll captured and briefly held San Antonio, and in turn led to a disastrous incursion by a pack of ill-disciplined Texians  south of the Rio Grande, which ended in their surrender at Ciudad Mier, Tamaulipas.[5]

After that second, abortive invasion, Texas flirted with Great Britain as a potential savior, but ultimately came to negotiate admission into the Union.[6]  Congress approved annexation in late 1844, and formal admission to the Union was approved on July 4, 1845 (with Texas formally joining the Union on December 29, 1845), thus setting the stage for a show-down with Mexico, which viewed Texian admission into the Union with a southern border on the Rio Grande as an act of provocation that would inevitably lead to war.[7]

But that analysis addresses only one aspect of U.S. sentiment in the early and mid-1840’s.  One must also consider the influence of the sense of many in the U.S. of their country’s “manifest destiny,” a term coined in the summer of 1845, either by John L. O’Sullivan or Jane McManus Storm.[8]  What “manifest destiny” really meant depended in large part on who was using it.[9]  The debate would continue through the course of the war and bear heavily on the negotiations that ultimately ended it.

The column in which “manifest destiney” first appeared explained that the term described U.S.’s providential mission to extend its “systems of democracy, federalism, and personal freedom, as well as to accommodate its rapidly growing population by taking possession of the entire North American continent,” which of course includes both Canada and Mexico.  Such expansion was proper because the U.S.’s “true title” to North America superseded that of any European power (to wit, Great Britain).  Hegemony was to be gained, not by war, but by “Anglo-Saxon emigration,” which would fill the wide-open spaces of the western half of the North America.  What O’Sullivan—or Storm, depending on your view—failed to mention was that the Irish and the Germans, who by that time were the most numerous emigrants to the United States, were manifestly not “Anglo-Saxon” by then-current usage of the term.[10]  Where the term was at issue lay in whether Manifest Destiny stopped at the Rio Grande to the south and the Canadian border to the north or whether it encompassed the notion that the United States and the North American continent would become more or less coterminous.[11]

President Polk embraced the general logic of manifest destiny by focusing in late 1845 and early 1846 (once Texas was admitted to the Union on December 29, 1845) on the question of what was to happen to Mexican-owned Alta California and its fine harbors in San Francisco (then Yerba Buena) and San Diego bays.  In the summer of 1845, Polk was warned by a U.S. merchant living in Monterey, Alta California (not be confused with Monterrey, Nuevo Leon), that the British and French potentially had designs on California.  Such concerns were not entirely unwarranted, as Mexico had indeed approached the British government about her fears of increasing U.S. encroachment and expansionism in the region.  But in the event the British were not interested, a point illustrated by the Oregon Treaty then being negotiated between Great Britain and the United States, which was signed on June 15, 1846, fixing the Canada/U.S. border in its present location.[12]

In November 1845, Polk further inflamed the situation when he sent John Slidell to Mexico as minister plenipotentiary with the brief of buying all of Mexico north of the Rio Grande to what is today New Mexico and thence west to the Pacific Ocean for as much as $40 million.[13]  Slidell’s mission seemed to the Mexican government to be a matter of “take or leave it”—and thus completely unacceptable to Mexico.[14]  Although Slidell was authorized to merely settle the adjustment of the Texas/Mexico border south to the Rio Grande, Mexico realized that this was merely to postpone the inevitable confrontation over California.  Thus was the Slidell Mission doomed from the start.

In March 1846, Slidell left, observing, “[d]epend upon it, we can never get along well with them, until we have given them a good drubbing.”[15]  The Democratic Party began to beat the drums for war in earnest and events on the ground began to move apace, as discussed below.

U.S. Perspective—the Anti-War Movement

Opposition to war with Mexico came from many corners of the U.S., not the least of which was New England, which contented itself to sit the war out, by effectively raising not a single regiment of volunteers.[16]  Other prominent opponents included a then-little known Illinois politician elected to the House of Representatives in the November 1846 mid-term election, in no small part based upon his opposition to the war, then in its early stages.

Opponents were to be found even in the army—to wit, Ulysses S. Grant, who wrote that the war was “the most unjust war ever waged by a stronger against a weaker nation … an instance of a republic following the bad example of European monarchies.”[17]  He was not alone.  Even Zachary Taylor, commander of the Army of Observation that began in August 1845 assembling outside Corpus Christi on the southern bank of the Nueces River initially opposed annexation of Texas and other lands.[18]  Taylor was a Whig, and he shared the concerns of his fellow Whigs about the expansion of slavery.[19]  This initial opposition gave way as Taylor assembled his army and eventually marched south to the Rio Grande.  Then-Lieutenant Colonel Ethan Allen Hitchcock, Colonel of the third Infantry Regiment, and one of Taylor’s principal lieutenants in the Army of Observation, was far more forthcoming in his diary about his opposition to the war.[20]  Although he missed the initial campaign in northern Mexico due to illness, he nonetheless returned to the war as Winfield Scott’s chief of spies (among other roles) during the Mexico City campaign, which culminated in the capture of Mexico City and the Treaty of Guadalupe-Hidalgo.

The question arises, why was opposition to the war so vociferous?  And why did it decrease so dramatically in the days and weeks after hostilities commence?

In a word, slavery.  Abolitionists had opposed admission of Texas as a slave state, and viewed the event as a terrible defeat and as evidence that slaveholders ruled the country.[21]  They opposed acquisition of California and New Mexico as potential slave states even more.  In their view, war and territorial expansion would consolidate the power of the South for a generation or more.  Quaker abolitionist John Greenleaf Whittier perhaps best captured the abolitionist’s views:  “Christian America, thanking God that she is not like other nations … goes out, Bible in hand, to enslave the world.”[22]

Whigs, who were generally the anti-slavery party, opposed entry into the war and voted against the May 1846 declaration of war that was put to a vote when news of the commencement of hostilities and the ambush of a squadron of U.S. cavalry reached Washington D.C.  But other than a small group, known as the Immortal Fourteen, congressional Whigs did not oppose funding and appropriations for the war on the theory that once war had begun, U.S. honor had to be preserved—which meant that the war had to be won.[23]

Attitudes did not soften as the war went on, and by the end of the war, anti-war abolitionists were all the more alienated from the then “prevailing values and governmental policy.”[24]  Conditions were ripe for a faction of abolitionists who, despairing of peacefully ending slavery, began to engage in violent acts seeking to bring an end to the institution.  Others helped form first the Free Soil Party and then the Republican Party.  Central to both parties were abolition and destroying the power of the slaveholding class.

Thus the war helped deepen the divide in the fabric of U.S. society and set the stage for the Civil War just a few years later.

From the Mexican Perspective—Never Yield Any Territory

Poor Mexico!  So far from God, so close to the United States![25]

So said Porfirio Diaz, and so John S.D. Eisenhower titled his fine history of the Mexican-American War.  Ramón Alcaraz wrote in the months after the end of the war:

The Mexican Republic, to whom nature had been prodigal, and full of those elements which make a great and happy nation, had among other misfortunes of less account, the great one of being in the vicinity of a strong and energetic the misfortune.[26]

In the eyes of many Mexicans, the United States recognized as soon as Mexico won its independence from Spain that Mexico “offered an easy conquest,” and thereafter “watched for a favorable moment for their project.”[27]  The tragedy that followed was thus inevitable.  First, the U.S. consumed the Louisiana Purchase, then Florida.  Texas was the next territory to be devoured, this time by virtue of emigration from the United States.  Mexico at first welcomed settlers with open arms as a bolster against the depredations of the Apache and Comanche.  But, as Alcaraz said, the “political inexperience” of Mexico’s rulers soon allowed the “benevolent and purely Christian principle” welcoming U.S. immigrants to transform into the “fountain of evils” that became the Texian War of Independence, a war that in the Mexican view the United States aided and abetted at every turn (as both a matter of official U.S. policy and actions and as a matter of broadly popular private support for the Texian revolution).[28]

With Texian independence won, the April 1844 treaty between the United States and Texas, paving the way to Texas’s formal admission to the Union on December 29, 1845, was little more than a foregone conclusion, and it should have spurred Mexico to war then, ill-prepared as she was to confront her stronger northern neighbor.[29]  Yet a new Mexican presidential administration still sought to negotiate to preserve Texas as an independent nation that could serve as a buffer between Mexico and the United States—to the great outcry from across the Mexican political spectrum that not an inch of Mexican soil should be yielded.  The United States sent the (intentionally in the Mexican view) ham-handed Slidell sission with the insulting insistence that Slidell be recognized as a minister plenipotentiary when the Mexican government insisted that the only point of negotiation was the future of Texas.[30]

The march of General Taylor’s Army of Observation to the Rio Bravo (as the Mexicans call the river) was an unmitigated act of war, because, in the Mexican view, no claim had ever hitherto been made that Texas extended that far south.  And why was this gambit made in the Mexican view?  Why of course to secure the border along the Rio Bravo (Rio Grande) all the way to New Mexico—a move preparatory to the U.S. acquiring the New Mexico and Alta California territories in addition to Texas.

From the Mexican Perspective—Conservatives and the Church

Mexican conservatives during the era from independence in 1821 until the execution of Emperor Maximilian in 1867 had virtually identical beliefs about governance that the Spanish—the hated Gachupine who were expelled after independence, to wit, that legitimate government in Mexico could be restored only by placing a European prince on a Mexican throne.[31]  They and the Catholic Church strove to restore Mexico to the wealthy colonial powerhouse it had been in the late 18th century, when Mexico City was the largest and wealthiest city in the Americas.

Mexican conservatives were every bit as opposed to the loss of Texas to the United States as the moderados and puros were (the latter being the two wings of liberals in pre-1846 Mexican politics).[32]  But that did not stop them from overthrowing the Herrera government at the end of 1845, and backing the new president, Paredes, who quickly realized the intractability of the crisis with the United States.  Herrera’s deposition in part led to Slidell reporting the failure of his mission, word of which reached Polk on January 12, 1846.  Polk then ordered Taylor south to the Rio Bravo (Rio Grande), which set in motion the clashes of April 1846 and the two battles north of the Rio Bravo in May 1846, which destroyed the Mexican army and forced the retreat of its remnants south to Monterrey, Nuevo Leon.  Paredes was deposed in August 1846, when news of those disasters reached Mexico City.

War was on, and the conservatives and the Church had done nothing to aid Mexico in her hour of need.  Matters were to get worse as the war progressed.  The Church would refuse to loan the Mexican government funds in late 1845, which led to what became known as the “Revolt of los Polkos,” so-named because the “dandified officers” of the National Guard (conservatives virtually to the man) had adopted an airy polka as the Guard’s anthem.[33]  The Church-backed revolt by the conservatives and the National Guard came as the Guard refused to deploy to Veracruz to oppose the imminent second invasion of Mexico by the United States.  The damage was done, and Mexico was left that much more vulnerable to defeat in the campaign of 1847, which resulted in the U.S. capture of Mexico City and the end of organized Mexican resistance in the war.[34]


The modern historiography of the Mexican American War is rich and varied, and the scholarship insightful.  Without such works focusing on the Mexican side as The View from Chapultepec, translated and edited by Cecil Robinson, which has a fine overview of the principal Mexican works on war, Gene M. Brack’s Mexico Views Manifest Destiny 1821-1846, and Pedro Santoni’s Mexicans at Arms: Puro Federalists and the Politics of War, researching the second, third and fourth volumes of General Gogan’s memoirs would have been impossible.  As I don’t read Spanish well enough, I could not access the dozen or so Mexican works of the past 30 years that appear only in that language.  I commend Cecil Robinson’s overview and the article entitled Historiography in Donald S. Frazier’s magnificent 1998 compendium, The Unted States and Mexico at War: Nineteenth Century Expansionism and Conflict, which both provide a nice summary of such works.

There are also, fortunately, several Mexican works from the nineteenth century available in either partial or full translation, which were equally as valuable, including Ramón Alcaraz’s 1848 work, Apuntes para la historia de la guerra entre México y los Estados Unidos (which in 1850 Albert C. Ramsey translated into English as The Other Side, or: Notes for the History of the War Between Mexico and the United States, Written in Mexico) and José Fernando Ramírez’s Mexico During the War with the United States (México Durante Su Guerra con los Estados Unidos)—which gives a fascinating behind-the-scenes account of life in Mexico City during the war, and which was translated into English in 1950.  Other 19th century works that are only available as excerpts in other books such as The View from Chapultepec, include Carlos Mariá Bustamente’s El Nuevo Bernal Díaz del Castillo, o sea, historia de la invasion de los anglo-americanos en México (1847), Manuel Balbontín’s Recuerdos de la invasion Americana (1883), and José Maria Barcena’s Recuerdos de la Invasion Norteamericana, 1846-1848, Por un Joven Ento (1887).

The U.S. side is almost an embarrassment of riches, both in terms of eyewitness memoirs and contemporaneous works (both of which must be approached in context of the times and the authors), later works such as Justin Smith’s War With Mexico (a standard work that must also be read cautiously) and a plethora over the past thirty or forty years of works as varied as Frazier’s compendium, Robert Johannsen’s To the Halls of the Montezumas, James M. McCaffrey’s Army of Manifest Destiny, and a dozen others.  As the General’s second volume is published, I will discuss these works in far more detail.

[1]       Paul Foos adopted the name for his wonderful book, A Short, Offhand, Killing Affair, which was subtitled, “Soldiers and Social Conflict During the Mexican-American War.” (Foos, 2002). Foos drew the name from Adolphus Wislizenus, who observed after narrowly escaping a lynching in Mexico that a mob there “is not that short, offhand killing affair that … [a mob] is in the far west of the United States.” Id. at 3.

[2]       [source]

[3]       The full title is Recuerdos de la Invasion Norteamericana, 1846-1848, Por un Joven Entonces. (Barcena, 1902)

[4]       The authorized strength of the U.S. Army in 1845 was 8,613 officers and enlisted men, but “desertion, illness, and vacancies had reduced the number below 5,500.”  (Frazier, 1998) at 24.

[5]       An wonderful recounting of the ill-fated Mier Expedition can be found in Sam Haynes’ book, Soldiers of Misfortune: The Somerville and Mier Expeditions.

[6]       David M. Pletcher does an excellent job of analyzing the intricacies of how the U.S. annexation of Oregon and Texas came about in his 1973 book, The Diplomacy of Annexation: Texas, Oregon and the Mexican War.

[7]       (Frazier, 1998) at 86.

[8]       (Frazier, 1998) at 234.  The term “Manifest Destiny” first appeared in an unsigned column in the Democratic Review.  Most commentators take the position that O’Sullivan, the Review’s editor, coined the term.  Linda S. Hudson claims in her book, Mistress of Manifest Destiny, Jane McManus Storm, who wrote for the Democratic Review under the pseudonym, “Montgomery,” actually wrote the column.  The General is likely to have something to say on the subject in subsequent books.

[9]       Although the term, “manifest destiny,” was of recent coinage, the concept dated back as far the beginning of the century, when Thomas Jefferson dreamed of U.S. expansion across the continent in his first inaugural address in 1801.  (Eisenhower, 1989) at xviii.  Jefferson, of course, was the architect of the 1803 Louisiana Purchase.

[10]     “Between 1841 and 1850, immigration nearly tripled … totaling 1,713,000 immigrants, including at least 781,000 Irish, 435,000 Germans, 267,000 British and 77,000 French immigrants.” (Wikipedia, 2009) at (accessed July 20, 2015).  Of these, only the “British,” (English, Scots and Welsh) were considered “Anglo-Saxon.”  [source].

[11]     (Frazier, 1998) at 234.

[12]     (Pletcher, 1974) at __.  As alluded to in Memoir of an American, in 1845 and early 1846, the U.S. faced the unappetizing prospect of war with both Britain and Mexico.  The Treaty of Oregon removed that threat, leaving the U.S. free to conduct its war with Mexico.  Id. at __.

[13]     Keep in mind that the United States paid an indemnity of $15 million as part of the Treaty of Guadalupe Hidalgo, which ended the war.  (Frazier, 1998) at 437-38.

[14]      (Robinson C. , 1989)   atxxvii.

[15]     (Frazier, 1998) at 87.

[16]     [source]

[17]     (Grant U. S., Personal Memoirs of U.S. Grant, Selected Letters 1839-1865, 1990) at 53.  Grant and Billy Gogan meet in the waters off St. Joesph’s Island, when Grant falls overboard as he disembarks from the transport that brought him and the Fourth Infantry to Texas, and Billy helps him to safety.

[18]     [source]

[19]     Taylor was a slaveholder, and thus unusual in being a Whig.  [source]

[20]     Hitchcock’s diary was eventually published posthumously as part of his memoir, Fifty Years of Camp and Field.  Hitchcock looms large in Manifest Destiny, the fourth book of the Billy Gogan saga.

[21]     (Frazier, 1998) at 1.

[22]     (Frazier, 1998) at 1.

[23]     (Frazier, 1998) at 214.

[24]     (Frazier, 1998) at 2.

[25]     Attributed to Porfirio Diaz, President of Mexico, 1877-1911.  (Eisenhower, 1989) at

[26]     (Alcaraz & Ramsey, 1850, 1970) at 1.

[27]     (Alcaraz & Ramsey, 1850, 1970) at 2.

[28]     (Alcaraz & Ramsey, 1850, 1970) at 16-22.

[29]     (Alcaraz & Ramsey, 1850, 1970) at 24-26.

[30]     (Alcaraz & Ramsey, 1850, 1970) at 28-29; (Robinson C. , 1989) at xxvi-xxvii (Robinson characterized the Slidell mission as “a classic example of cultural blundering on the part of the United States in its dealings with Mexico”).

[31]     (Robinson C. , 1989) at xviii.

[32]     (Robinson C. , 1989) at xix-xxii.

[33]     (Robinson C. , 1989) at xii-xiii.

[34]     General Gogan was an eye witness to and participant in these remarkable events in February 1847.  He recounts these adventures in the third volume of his memoirs, entitled Sheltered by the Enemy.

A Documentary About the Mexican-American War

History Channel’s Mexican American War – (Part 1 of 6)

History Channel’s Mexican American War – (Part 4 of 6)

History Channel’s Mexican American War – (Part 2 of 6)

History Channel’s Mexican American War – (Part 5 of 6)

History Channel’s Mexican American War – (Part 3 of 6)

History Channel’s Mexican American War – (Part 6 of 6)

Pin It on Pinterest

Share This