|Mexican–American War from Wikipedia
The Mexican–American War, also known as the First American
Intervention, the Mexican War, or the U.S.–Mexican War, was an armed conflict
between the United States and Mexico from 1846 to 1848 in the wake of the
1845 U.S. annexation of Texas, which Mexico considered part of its territory
despite the 1836 Texas Revolution.
American forces invaded New Mexico, the California Republic,
and parts of what is currently northern Mexico; meanwhile, the American
Navy conducted a blockade, and took control of several garrisons on the
Pacific coast of Alta California, but also further south in Baja California.
Another American army captured Mexico City, and forced Mexico to agree
to the cession of its northern territories to the U.S.
American territorial expansion to the Pacific coast was
the goal of President James K. Polk, the leader of the Democratic Party.
However, the war was highly controversial in the U.S., with the Whig Party
and anti-slavery elements strongly opposed. Heavy American casualties and
high monetary cost were also criticized. The major consequence of the war
was the forced Mexican Cession of the territories of Alta California and
New Mexico to the U.S. in exchange for $18 million. In addition, the United
States forgave debt owed by the Mexican government to U.S. citizens. Mexico
accepted the Rio Grande as its national border, and the loss of Texas.
The political aftermath of the war raised the slavery issue in the U.S.,
leading to intense debates that pointed to civil war; the Compromise of
1850 provided a brief respite.
In Mexico, terminology for the war include (primera) intervención
estadounidense en México (United States' (First) Intervention in
Mexico), invasión estadounidense de México (The United States'
Invasion of Mexico), and guerra del 47 (The War of 1847).
Mexico was torn apart by bitter internal political battles
that verged on civil war, even as it was united in refusing to recognize
the independence of Texas. Mexico threatened war with the U.S. if it annexed
Texas. Meanwhile President Polk's spirit of Manifest Destiny was focusing
U.S. interest on westward expansion
Designs on California
In 1842, the American minister in Mexico Waddy Thompson,
Jr. suggested Mexico might be willing to cede California to settle debts,
saying: "As to Texas I regard it as of very little value compared with
California, the richest, the most beautiful and the healthiest country
in the world ... with the acquisition of Upper California we should have
the same ascendency on the Pacific ... France and England both have had
their eyes upon it." President John Tyler's administration suggested a
tripartite pact that would settle the Oregon boundary dispute and provide
for the cession of the port of San Francisco; Lord Aberdeen declined to
participate but said Britain had no objection to U.S. territorial acquisition
For his part, the British minister in Mexico Richard Pakenham
wrote in 1841 to Lord Palmerston urging "to establish an English population
in the magnificent Territory of Upper California," saying that "no part
of the World offering greater natural advantages for the establishment
of an English colony ... by all means desirable ... that California, once
ceasing to belong to Mexico, should not fall into the hands of any power
but England ... daring and adventurous speculators in the United States
have already turned their thoughts in this direction." But by the time
the letter reached London, Sir Robert Peel's Tory government with a Little
England policy had come to power and rejected the proposal as expensive
and a potential source of conflict.
Republic of Texas
Origins of the war
The Republic of Texas. The present-day
outlines of the U.S. states are
superimposed on the boundaries
|In 1810, Moses Austin, a banker from Missouri, was granted
a large tract of land in Texas, but died before he could bring his plan
of recruiting American settlers for the land to fruition. His son, Stephen
F. Austin, succeeded and brought over 300 families into Texas, which started
the steady trend of American migration into the Texas frontier. Austin's
colony was the most successful of several colonies authorized by the Mexican
government. The Mexican government intended the anglophone settlers to
act as a buffer between the existing Mexican residents and the marauding
Comanches, but the anglo colonists tended to settle where there was decent
farmland, rather than where they would have been an effective buffer. In
1829, as a result of the large influx of American immigrants, the Americans
outnumbered Mexicans in the Texas territory. The Mexican government decided
to bring back the property tax, increase tariffs on U.S. shipped goods,
and prohibit slavery. The settlers rejected the demands, which led to Mexico
closing Texas to additional immigration. However, Americans continued to
flow into the Texas territory.
In 1834, General Antonio López de Santa Anna became
the dictator of Mexico, abandoning the federal system. He decided to squash
the semi-independence of Texas. Stephen F. Austin called Texans to arms;
they declared independence from Mexico in 1836, and after Santa Anna defeated
the Texans at the Alamo (causing his army nearly three weeks' delay), he
was defeated by the Texan Army commanded by General Sam Houston and captured
at the Battle of San Jacinto and signed a treaty recognizing Texas independence.
Texas consolidated its status as an independent republic, winning official
recognition from Britain, France, and the U.S., which all advised Mexico
not to try to reconquer the new nation. Most Texans wanted to join the
U.S. but annexation of Texas was contentious in the U.S. Congress, where
Whigs were largely opposed. In 1845 Texas agreed to the offer of annexation
by the U.S. Congress. Texas became the 28th state on December 29, 1845.
The Mexican government had long warned the United States
that annexation of Texas would mean war. Because the Mexican Congress had
refused to recognize Texan independence, Mexico saw Texas as a rebellious
territory that would be retaken. Britain and France, which recognized the
independence of Texas, repeatedly tried to dissuade Mexico from declaring
war. When Texas joined the U.S. as a state in 1845, the Mexican government
broke diplomatic relations with the U.S.
The border of Texas as an independent state had never
been settled. The Republic of Texas claimed land up to the Rio Grande based
on the Treaties of Velasco, but Mexico refused to accept these as valid,
claiming the border as the Nueces River. Reference to the Rio Grande boundary
of Texas was omitted from the U.S. Congress' annexation resolution to help
secure passage after the annexation treaty failed in the Senate. President
Polk claimed the Rio Grande boundary, and this provoked a dispute with
Mexico. In June 1845, Polk sent General Zachary Taylor to Texas, and by
October 3,500 Americans were on the Nueces River, prepared to defend Texas
from a Mexican invasion. Polk wanted to protect the border and also coveted
the continent clear to the Pacific Ocean. Polk had instructed the Pacific
naval squadron to seize the California ports if Mexico declared war while
staying on good terms with the inhabitants. At the same time he wrote to
Thomas Larkin, the American consul in Alta California, disclaiming American
ambitions in California but offering to support independence from Mexico
or voluntary accession to the U.S., and warning that a British or French
takeover would be opposed.
To end another war-scare (Fifty-Four Forty or Fight) with
Britain over Oregon Country, Polk signed the Oregon Treaty dividing the
territory, angering northern Democrats who felt he was prioritizing Southern
expansion over Northern expansion.
In the winter of 1845–46, the federally commissioned explorer
John C. Frémont and a group of armed men appeared in California.
After telling the Mexican governor and Larkin he was merely buying supplies
on the way to Oregon, he instead entered the populated area of California
and visited Santa Cruz and the Salinas Valley, explaining he had been looking
for a seaside home for his mother. The Mexican authorities became alarmed
and ordered him to leave. Fremont responded by building a fort on Gavilan
Peak and raising the American flag. Larkin sent word that his actions were
counterproductive. Fremont left California in March but returned to California
and assisted the Bear Flag Revolt in Sonoma, where many American immigrants
stated that they were playing “the Texas game” and declared California’s
independence from Mexico.
On November 10, 1845, Polk sent John Slidell, a secret
representative, to Mexico City with an offer of $25 million ($632,500,000
today) for the Rio Grande border in Texas and Mexico’s provinces of Alta
California and Santa Fe de Nuevo México. U.S. expansionists wanted
California to thwart British ambitions in the area and to gain a port on
the Pacific Ocean. Polk authorized Slidell to forgive the $3 million ($76
million today) owed to U.S. citizens for damages caused by the Mexican
War of Independence and pay another $25 to $30 million ($633 million to
$759 million today) in exchange for the two territories.
Mexico was not inclined nor able to negotiate. In 1846
alone, the presidency changed hands four times, the war ministry six times,
and the finance ministry sixteen times. However, Mexican public opinion
and all political factions agreed that selling the territories to the United
States would tarnish the national honor. Mexicans who opposed direct conflict
with the United States, including President José Joaquín
de Herrera, were viewed as traitors. Military opponents of de Herrera,
supported by populist newspapers, considered Slidell's presence in Mexico
City an insult. When de Herrera considered receiving Slidell to settle
the problem of Texas annexation peacefully, he was accused of treason and
deposed. After a more nationalistic government under General Mariano Paredes
y Arrillaga came to power, it publicly reaffirmed Mexico's claim to Texas;
Slidell, convinced that Mexico should be "chastised", returned to the U.S.
Conflict over the Nueces Strip
President Polk ordered General Taylor and his forces south
to the Rio Grande, entering the territory that Mexicans disputed. Mexico
laid claim to the Nueces River—about 150 mi (240 km) north of the Rio Grande—as
its border with Texas; the U.S. claimed it was the Rio Grande, citing the
1836 Treaties of Velasco. Mexico, however, under the leadership of General
Lorenzo Chlamon, rejected the treaties and refused to negotiate; it claimed
all of Texas. Taylor ignored Mexican demands to withdraw to the Nueces.
He constructed a makeshift fort (later known as Fort Brown/Fort Texas)
on the banks of the Rio Grande opposite the city of Matamoros, Tamaulipas.
Mexican forces under General Mariano Arista prepared for war. On April
25, 1846, a 2,000-strong Mexican cavalry detachment attacked a 70-man U.S.
patrol that had been sent into the contested territory north of the Rio
Grande and south of the Nueces River. The Mexican cavalry routed the patrol,
killing 16 U.S. soldiers in what later became known as the Thornton Affair,
after Captain Thornton, who was in command.
Declaration of war
Opposition to the war
Overview map of the war
|Polk received word of the Thornton Affair, which, added
to the Mexican government's rejection of Slidell, Polk believed, constituted
a casus belli (case for war). His message to Congress on May 11, 1846 stated
that "Mexico has passed the boundary of the United States, has invaded
our territory and shed American blood upon American soil." Congress approved
the declaration of war on May 13, with southern Democrats in strong support.
Sixty-seven Whigs voted against the war on a key slavery amendment, but
on the final passage only 14 Whigs voted no, including Rep. John Quincy
Adams. Congress declared war on Mexico on May 13, 1846 after only having
a few hours to debate. Although President Paredes's issuance of a manifesto
on May 23 is sometimes considered the declaration of war, Mexico officially
declared war by Congress on July 7.
Antonio Lopez de Santa Anna
Once the U.S. declared war on Mexico, Antonio López
de Santa Anna wrote to Mexico City saying he no longer had aspirations
to the presidency, but would eagerly use his military experience to fight
off the foreign invasion of Mexico as he had before. President Valentín
Gómez Farías was desperate enough to accept the offer and
allowed Santa Anna to return. Meanwhile, Santa Anna had secretly been dealing
with representatives of the U.S., pledging that if he were allowed back
in Mexico through the U.S. naval blockades, he would work to sell all contested
territory to the United States at a reasonable price. Once back in Mexico
at the head of an army, Santa Anna reneged on both agreements. Santa Anna
declared himself president again and unsuccessfully tried to fight off
the U.S. invasion.
In the U.S., increasingly divided by sectional rivalry,
the war was a partisan issue and an essential element in the origins of
the American Civil War. Most Whigs in the North and South opposed it; most
Democrats supported it. Southern Democrats, animated by a popular belief
in Manifest Destiny, supported it in hopes of adding slave-owning territory
to the South and avoiding being outnumbered by the faster-growing North.
John O'Sullivan, the editor of the "Democratic Review", coined this phrase
in its context, stating that it must be "Our manifest destiny to overspread
the continent alloted by Providence for the free development of our yearly
multiplying millions." Northern anti-slavery elements feared the rise of
a Slave Power; Whigs generally wanted to strengthen the economy with industrialization,
not expand it with more land. Democrats wanted more land; northern Democrats
were attracted by the possibilities in the far northwest. Joshua Giddings
led a group of dissenters in Washington D.C. He called the war with Mexico
"an aggressive, unholy, and unjust war," and voted against supplying soldiers
and weapons. He said:
|In the murder of Mexicans upon their own soil, or in
robbing them of their country, I can take no part either now or here-after.
The guilt of these crimes must rest on others. I will not participate in
Fellow Whig Abraham Lincoln contested the causes for the
war and demanded to know exactly where Thornton had been attacked and American
blood shed. "Show me the spot," he demanded. Whig leader Robert Toombs
of Georgia declared:
This war is nondescript .... We charge
the President with usurping the war-making power ... with seizing a country
... which had been for centuries, and was then in the possession of the
Mexicans .... Let us put a check upon this lust of dominion. We had territory
enough, Heaven knew.
Northern abolitionists attacked the war as an attempt
by slave-owners to strengthen the grip of slavery and thus ensure their
continued influence in the federal government. Acting on his convictions,
Henry David Thoreau was jailed for his refusal to pay taxes to support
the war, and penned his famous essay, Civil Disobedience.
Former President John Quincy Adams also expressed his
belief that the war was primarily an effort to expand slavery in a speech
he gave before the House on May 25, 1836. In response to such concerns,
Democratic Congressman David Wilmot introduced the Wilmot Proviso, which
aimed to prohibit slavery in new territory acquired from Mexico. Wilmot's
proposal did not pass Congress, but it spurred further hostility between
Defense of the war
Besides alleging that the actions of Mexican military
forces within the disputed boundary lands north of the Rio Grande constituted
an attack on American soil, the war's advocates viewed the territories
of New Mexico and California as only nominally Mexican possessions with
very tenuous ties to Mexico, and as actually unsettled, ungoverned, and
unprotected frontier lands, whose non-aboriginal population, where there
was any at all, comprised a substantial—in places even a majority—American
component, and which were feared to be under imminent threat of acquisition
by America's rival on the continent, the British.
President Polk reprised these arguments in his Third Annual
Message to Congress on December 7, 1847, in which he scrupulously detailed
his administration's position on the origins of the conflict, the measures
the U.S. had taken to avoid hostilities, and the justification for declaring
war. He also elaborated upon the many outstanding financial claims by American
citizens against Mexico and argued that, in view of the country's insolvency,
the cession of some large portion of its northern territories was the only
indemnity realistically available as compensation. This helped to rally
Congressional Democrats to his side, ensuring passage of his war measures
and bolstering support for the war in the U.S.
The Siege of Fort Texas began on May 3. Mexican artillery
at Matamoros opened fire on Fort Texas, which replied with its own guns.
The bombardment continued for 160 hours and expanded as Mexican forces
gradually surrounded the fort. Thirteen U.S. soldiers were injured during
the bombardment, and two were killed. Among the dead was Jacob Brown, after
whom the fort was later named.
On May 8, Zachary Taylor and 2,400 troops arrived to relieve
the fort. However, Arista rushed north and intercepted him with a force
of 3,400 at Palo Alto. The Americans employed "flying artillery", the American
term for horse artillery, a type of mobile light artillery that was mounted
on horse carriages with the entire crew riding horses into battle. It had
a devastating effect on the Mexican army. The Mexicans replied with cavalry
skirmishes and their own artillery. The U.S. flying artillery somewhat
demoralized the Mexican side, and seeking terrain more to their advantage,
the Mexicans retreated to the far side of a dry riverbed (resaca) during
the night. It provided a natural fortification, but during the retreat,
Mexican troops were scattered, making communication difficult. During the
Battle of Resaca de la Palma the next day, the two sides engaged in fierce
hand to hand combat. The U.S. cavalry managed to capture the Mexican artillery,
causing the Mexican side to retreat—a retreat that turned into a rout.
Fighting on unfamiliar terrain, his troops fleeing in retreat, Arista found
it impossible to rally his forces. Mexican casualties were heavy, and the
Mexicans were forced to abandon their artillery and baggage. Fort Brown
inflicted additional casualties as the withdrawing troops passed by the
fort. Many Mexican soldiers drowned trying to swim across the Rio Grande.
Conduct of the war
After the declaration of war, U.S. forces invaded Mexican
territory on two main fronts. The U.S. War Department sent a U.S. cavalry
force under Stephen W. Kearny to invade western Mexico from Jefferson Barracks
and Fort Leavenworth, reinforced by a Pacific fleet under John D. Sloat.
This was done primarily because of concerns that Britain might also try
to seize the area. Two more forces, one under John E. Wool and the other
under Taylor, were ordered to occupy Mexico as far south as the city of
Although the U.S. declared war against Mexico on May 13,
1846, it took over a month (until the middle of June 1846) for definite
word of war to get to California. American consul Thomas O. Larkin, stationed
in Monterey, on hearing rumors of war tried to maintain the peace between
the States and the small Mexican military garrison commanded by José
Castro. U.S. Army captain John C. Frémont, with about 60 well-armed
men, had entered California in December, 1845, and was slowly marching
to Oregon when he received word that war between Mexico and the U.S. was
imminent. So began his chapter of the war, the "Bear Flag Revolt."
A replica of the first "Bear Flag"
now at El Presidio de Sonoma,
or Sonoma Barracks
|On June 15, 1846, some thirty settlers, mostly American
citizens, staged a revolt and seized the small Mexican garrison in Sonoma.
They raised the "Bear Flag" of the California Republic over Sonoma. The
republic was in existence scarcely more than a week before the U.S. Army,
led by Frémont, took over on June 23. The California state flag
today is based on this original Bear Flag and still contains the words,
Commodore John Drake Sloat, upon hearing of imminent war
and the revolt in Sonoma, ordered his naval and marine forces to occupy
Monterey, the capital, on July 7 and raise the flag of the U.S.; San Francisco,
then called Yerba Buena, was occupied on July 9. On July 15, Sloat transferred
his command to Commodore Robert F. Stockton, a much more aggressive leader,
who put Frémont's forces under his orders. On July 19, Frémont's
"California Battalion" swelled to about 160 additional men from newly arrived
settlers near Sacramento, and he entered Monterey in a joint operation
with some of Stockton's sailors and marines. The word had been received:
war was official. The U.S. forces easily took over the north of California;
within days they controlled San Francisco, Sonoma, and the privately owned
Sutter's Fort in Sacramento.
From Alta California (the present-day American state of
California), Mexican General José Castro and Governor Pío
Pico fled southward. When Stockton's forces, sailing southward to San Diego,
stopped in San Pedro, he sent 50 U.S. Marines ashore; this force entered
Los Angeles unresisted on August 13, 1846. With the success of this so-called
"Siege of Los Angeles", the nearly bloodless conquest of California seemed
Stockton, however, left too small a force in Los Angeles,
and the Californios, acting on their own, and without help from Mexico,
led by José María Flores, forced the American garrison to
retreat, late in September. The rancho vaqueros who had banded together
to defend their land fought as Californio lancers; they were a force the
Americans had not anticipated. More than three hundred American reinforcements,
sent by Stockton and led by Captain William Mervine, U.S.N., were repulsed
in the Battle of Dominguez Rancho, fought from October 7 through 9, 1846,
near San Pedro. Fourteen American Marines were killed.
Meanwhile, General Stephen W. Kearny, with a squadron
of 139 dragoons that he had led on a grueling march across New Mexico,
Arizona, and the Sonoran Desert, finally reached California on December
6, 1846, and fought in a small battle with Californio lancers at the Battle
of San Pasqual near San Diego, California, where 22 of Kearny's troops
Kearny's command was bloodied and in poor condition but
pushed on until they had to establish a defensive position on "Mule" Hill
near present-day Escondido. The Californios besieged the dragoons for four
days until Commodore Stockton's relief force arrived. The resupplied, combined
American force marched north from San Diego on December 29 and entered
the Los Angeles area on January 8, 1847, linking up with Frémont's
men there. American forces totalling 607 soldiers and marines fought and
defeated a Californio force of about 300 men under the command of Captain-general
Flores in the decisive Battle of Rio San Gabriel. The next day, January
9, 1847, the Americans fought and won the Battle of La Mesa. On January
12, the last significant body of Californios surrendered to U.S. forces.
That marked the end of armed resistance in California, and the Treaty of
Cahuenga was signed the next day, on January 13, 1847.
Pacific Coast campaign
USS Independence assisted in the blockade of the Mexican
Pacific coast, capturing the Mexican ship Correo and a launch on 16 May
1847. She supported the capture of Guaymas, Mexico, on 19 October 1847
and landed bluejackets and Marines to occupy Mazatlán, Mexico on
11 November 1847. After upper California was secure most of the Pacific
Squadron proceeded down the California coast capturing all major Baja California
cities and capturing or destroying nearly all Mexican vessels in the Gulf
of California. Other ports, not on the peninsula, were taken as well. The
objective of the Pacific Coast Campaign was to capture Mazatlan, a major
supply base for Mexican forces. Numerous Mexican ships were also captured
by this squadron with the USS Cyane given credit for 18 captures and numerous
destroyed ships. Entering the Gulf of California, Independence, Congress
and Cyane seized La Paz captured and burned the small Mexican fleet at
Guaymas. Within a month, they cleared the Gulf of hostile ships, destroying
or capturing 30 vessels. Later on their sailors and marines captured the
town of Mazatlan, Mexico, on 11 November 1847. A Mexican campaign under
Manuel Pineda to retake the various captured ports resulted in several
small clashes (Battle of Mulege, Battle of La Paz, Battle of San José
del Cabo) and two sieges (Siege of La Paz, Siege of San José del
Cabo) in which the Pacific Squadron ships provided artillery support. U.S.
garrisons remained in control of the ports and following reinforcement,
Lt. Col. Henry S. Burton marched out, rescued captured Americans, captured
Pineda and on March 31, defeated and dispersed remaining Mexican forces
at the Skirmish of Todos Santos, unaware the Treaty of Guadalupe Hidalgo
had been signed in February 1848. When the American garrisons were evacuated
following the treaty, many Mexicans that had been supporting the American
cause and had thought Lower California would also be annexed like Upper
California, were evacuated with them to Monterey.
The defeats at Palo Alto and Resaca de la Palma caused
political turmoil in Mexico, turmoil which Antonio López de Santa
Anna used to revive his political career and return from self-imposed exile
in Cuba in mid-August 1846. He promised the U.S. that if allowed to pass
through the blockade, he would negotiate a peaceful conclusion to the war
and sell the New Mexico and Alta California territories to the U.S. Once
Santa Anna arrived in Mexico City, however, he reneged and offered his
services to the Mexican government. Then, after being appointed commanding
general, he reneged again and seized the presidency.
Led by Taylor, 2,300 U.S. troops crossed the Rio Grande
(Rio Bravo) after some initial difficulties in obtaining river transport.
His soldiers occupied the city of Matamoros, then Camargo (where the soldiery
suffered the first of many problems with disease) and then proceeded south
and besieged the city of Monterrey. The hard-fought Battle of Monterrey
resulted in serious losses on both sides. The American light artillery
was ineffective against the stone fortifications of the city. The Mexican
forces were under General Pedro de Ampudia and repulsed Taylor's best infantry
division at Fort Teneria. American soldiers, including many West Pointers,
had never engaged in urban warfare before and they marched straight down
the open streets, where they were annihilated by Mexican defenders well-hidden
in Monterrey's thick adobe homes. Two days later, they changed their urban
warfare tactics. Texan soldiers had fought in a Mexican city before and
advised Taylor's generals that the Americans needed to "mouse hole" through
the city's homes. In other words, they needed to punch holes in the side
or roofs of the homes and fight hand to hand inside the structures. This
method proved successful and Ampudia eventually surrendered.
entrenched position. The Mexicans had inflicted considerable
losses but Santa Anna had gotten word of upheaval in Mexico City, so he
withdrew that night, leaving Taylor in control of part of Northern Mexico.
Polk distrusted Taylor, whom he felt had shown incompetence in the Battle
of Monterrey by agreeing to the armistice, and may have considered him
a political rival for the White House. Taylor later used the Battle of
Buena Vista as the centerpiece of his successful 1848 presidential campaign.
|Eventually, these actions drove and trapped Ampudia's
men into the city's central plaza, where howitzer shelling forced Ampudia
to negotiate. Taylor agreed to allow the Mexican Army to evacuate and to
an eight-week armistice in return for the surrender of the city. Under
pressure from Washington, Taylor broke the armistice and occupied the city
of Saltillo, southwest of Monterrey. Santa Anna blamed the loss of Monterrey
and Saltillo on Ampudia and demoted him to command a small artillery battalion.
On February 22, 1847, Santa Anna personally marched north to fight Taylor
with 20,000 men. Taylor, with 4,600 men, had entrenched at a mountain pass
called Buena Vista. Santa Anna suffered desertions on the way north and
arrived with 15,000 men in a tired state. He demanded and was refused surrender
of the U.S. Army; he attacked the next morning. Santa Anna flanked the
U.S. positions by sending his cavalry and some of his infantry up the steep
terrain that made up one side of the pass, while a division of infantry
attacked frontally along the road leading to Buena Vista. Furious fighting
ensued, during which the U.S troops were nearly routed, but managed to
cling to their
Battle of Monterrey
On March 1, 1847, Alexander W. Doniphan occupied Chihuahua
City. He found the inhabitants much less willing to accept the American
conquest than the New Mexicans. The British consul John Potts did not want
to let Doniphan search Governor Trias's mansion, and unsuccessfully asserted
it was under British protection. American merchants in Chihuahua wanted
the American force to stay in order to protect their business. Gilpin advocated
a march on Mexico City and convinced a majority of officers, but Doniphan
subverted this plan, then in late April Taylor ordered the First Missouri
Mounted Volunteers to leave Chihuahua and join him at Saltillo. The American
merchants either followed or returned to Santa Fe. Along the way, the townspeople
of Parras enlisted Doniphan's aid against an Indian raiding party that
had taken children, horses, mules, and money.
The civilian population of northern Mexico offered little
resistance to the American invasion possibly because the country had already
been devastated by Comanche and Apache Indian raids. Josiah Gregg, who
was with the American army in northern Mexico, said that “the whole country
from New Mexico to the borders of Durango is almost entirely depopulated.
The haciendas and ranchos have been mostly abandoned, and the people chiefly
confined to the towns and cities.”
U.S. press and popular war enthusiasm
During the war inventions such as the telegraph created
new means of communication that updated people with the latest news from
the reporters, who were usually on the scene. With more than a decade’s
experience reporting urban crime, the “penny press” realized the voracious
need of the public to get the astounding war news. This was the first time
in the American history when the accounts by journalists, instead of the
opinions of politicians, caused great influence in shaping people’s minds
and attitudes toward a war. News about the war always caused extraordinary
By getting constant reports from the battlefield, Americans
became emotionally united as a community. In the spring of 1846, news about
Zachary Taylor's victory at Palo Alto brought up a large crowd that met
in a cotton textile town of Lowell, Massachusetts. At Veracruz and Buena
Vista, New York celebrated their twin victories in May 1847. Among fireworks
and illuminations, they had a “grand procession” of about 400,000 people.
Generals Taylor and Scott became heroes for their people and later became
Several hundred deserters went over to the Mexican side;
nearly all were recent immigrants from Europe with weak ties to the U.S.,
the most famous group being Saint Patrick's Battalion, about half of whom
were Catholics from Ireland. The Mexicans issued broadsides and leaflets
enticing U.S. soldiers with promises of money, land bounties, and officers'
commissions. Mexican guerrillas shadowed the U.S. Army and captured men
who took unauthorized leave or fell out of the ranks. The guerrillas coerced
these men to join the Mexican ranks. The generous promises proved illusory
for most deserters, who risked being executed, if captured by U.S. forces.
About 50 of the San Patricios were tried and hanged following their capture
at Churubusco in August 1847.
|The desertion rate was a major problem for the Mexican
army, depleting forces on the eve of battle. Most of the soldiers were
peasants who had a loyalty to their village and family, but not to the
generals who conscripted them. Often hungry and ill, never well paid, under-equipped
and only partially trained, the soldiers were held in contempt by their
officers and had little reason to fight the Americans. Looking for their
opportunity, many slipped away from camp to find their way back to their
The desertion rate in the U.S. army was 8.3% (9,200 out
of 111,000), compared to 12.7% during the War of 1812 and usual peacetime
rates of about 14.8% per year. Many men deserted to join another U.S. unit
and get a second enlistment bonus. While some deserted because of the miserable
conditions in camp, it has been suggested that others used the army to
get free transportation to California, where they deserted to join the
gold rush. This, however, is unlikely as gold was only discovered in California
on January 24, 1848, less than two weeks before the war concluded. By the
time word reached the eastern U.S. that gold had been discovered, word
also reached it that the war was over.
Battle of Churubusco by J. Cameron,
published by Nathaniel Currier.
Hand tinted lithograph, 1847. Digitally restored.
Scott's Mexico City campaign
Advance on Puebla
Battle of Chapultepec
|Landings and Siege of Vera Cruz
Rather than reinforce Taylor's army for a continued advance,
President Polk sent a second army under General Winfield Scott, which was
transported to the port of Veracruz by sea, to begin an invasion of the
Mexican heartland. On March 9, 1847, Scott performed the first major amphibious
landing in U.S. history in preparation for the Siege of Veracruz. A group
of 12,000 volunteer and regular soldiers successfully offloaded supplies,
weapons, and horses near the walled city using specially designed landing
craft. Included in the invading force were Robert E. Lee, George Meade,
Ulysses S. Grant, James Longstreet, and Thomas "Stonewall" Jackson. The
city was defended by Mexican General Juan Morales with 3,400 men. Mortars
and naval guns under Commodore Matthew C. Perry were used to reduce the
city walls and harass defenders. The city replied the best it could with
its own artillery. The effect of the extended barrage destroyed the will
of the Mexican side to fight against a numerically superior force, and
they surrendered the city after 12 days under siege. U.S. troops suffered
80 casualties, while the Mexican side had around 180 killed and wounded,
about half of whom were civilian. During the siege, the U.S. side began
to fall victim to yellow fever.
Scott then marched westward toward Mexico City with 8,500
healthy troops, while Santa Anna set up a defensive position in a canyon
around the main road at the halfway mark to Mexico City, near the hamlet
of Cerro Gordo. Santa Anna had entrenched with 12,000 troops and artillery
that were trained on the road, along which he expected Scott to appear.
However, Scott had sent 2,600 mounted dragoons ahead, and the Mexican artillery
prematurely fired on them and revealed their positions. Instead of taking
the main road, Scott's troops trekked through the rough terrain to the
north, setting up his artillery on the high ground and quietly flanking
the Mexicans. Although by then aware of the positions of U.S. troops, Santa
Anna and his troops were unprepared for the onslaught that followed. The
Mexican army was routed. The U.S. Army suffered 400 casualties, while the
Mexicans suffered over 1,000 casualties and 3,000 were taken prisoner.
In August 1847, Captain Kirby Smith, of Scott's 3rd Infantry, reflected
on the resistance of the Mexican army:
|What stupid people they are! They can do nothing and
their continued defeats should convince them of it. They have lost six
great battles; we have captured six hundred and eight cannon, nearly one
hundred thousand stands of arms, made twenty thousand prisoners, have the
greatest portion of their country and are fast advancing on their Capital
which must be ours,—yet they refuse to treat [i.e., negotiate terms]!
Pause at Puebla
In May, Scott pushed on to Puebla, the second largest
city in Mexico. Because of the citizens' hostility to Santa Anna, the city
capitulated without resistance on May 1. During the following months Scott
gathered supplies and reinforcements at Puebla and sent back units whose
enlistments had expired. Scott also made strong efforts to keep his troops
disciplined and treat the Mexican people under occupation justly, so as
to prevent a popular rising against his army.
Advance on Mexico City and its capture
With guerrillas harassing his line of communications back
to Vera Cruz, Scott decided not to weaken his army to defend it but, leaving
only a garrison at Puebla to protect the sick and injured recovering there,
advanced on Mexico City on August 7, with his remaining force. The capital
was laid open in a series of battles around the right flank of the city
defenses, culminating in the Battle of Chapultepec. With the subsequent
storming of the city gates, the capital was occupied. Winfield Scott became
an American national hero after his victories in this campaign of the Mexican–American
War, and later became military governor of occupied Mexico City.
Santa Anna's last campaign
In late September 1847, Santa Anna made one last attempt
to defeat the Americans, by cutting them off from the coast. General Joaquín
Rea began the Siege of Puebla, soon joined by Santa Anna, but they failed
to take it before the approach of a relief column from Vera Cruz under
Brig. Gen. Joseph Lane prompted Santa Anna to stop him. Puebla was relieved
by Gen. Lane October 12, 1847, following his defeat of Santa Anna at the
Battle of Huamantla October 9, 1847. The battle was Santa Anna's last.
Following the defeat, the new Mexican government led by Manuel de la Peña
y Peña asked Santa Anna to turn over command of the army to General
José Joaquín de Herrera.
Anti guerrilla campaign
Following his capture and securing of the capital, General
Scott sent about a quarter of his strength to secure his line of communications
to Vera Cruz from the Light Corps and other Mexican guerilla forces that
had been harassing it since May. He strengthened the garrison of Puebla,
and by November established 750 man posts at Perote, Puente Nacional, Rio
Frio, and San Juan along the National Road and detailed an antiguerrilla
brigade under Brig. Gen. Joseph Lane to carry the war to the Light Corps
and other guerillas. He also ordered that convoys would travel with at
least 1,300-man escorts. Despite some victories over General Joaquín
Rea at Atlixco (18 October 1847) and Izucar de Matamoros (in November)
by General Lane, guerrilla raids on the supply route continued into 1848
until the end of the war.
Treaty of Guadalupe Hidalgo
The Mexican Cession, shown in red,
and the later Gadsden Purchase,
shown in yellow.
|Outnumbered militarily and with many of its large cities
occupied, Mexico could not defend itself and was also faced with internal
divisions. It had little choice but to make peace on any terms. The Treaty
of Guadalupe Hidalgo, signed on February 2, 1848, by American diplomat
Nicholas Trist and Mexican plenipotentiary representatives Luis G. Cuevas,
Bernardo Couto, and Miguel Atristain, ended the war and gave the U.S. undisputed
control of Texas, established the U.S.-Mexican border of the Rio Grande
River, and ceded to the United States the present-day states of California,
Nevada, Utah, New Mexico, most of Arizona and Colorado, and parts of Texas,
Oklahoma, Kansas, and Wyoming. In return, Mexico received US $18,250,000
($461,725,000 today)—less than half the amount the U.S. had attempted to
offer Mexico for the land before the opening of hostilities—and the U.S.
agreed to assume $3.25-million ($82,225,000 today) in debts that the Mexican
government owed to U.S. citizens.
The acquisition was a source of controversy then, especially
among U.S. politicians who had opposed the war from the start. A leading
antiwar U.S. newspaper, the Whig Intelligencer sardonically concluded that
"We take nothing by conquest .... Thank God."
Article IX (which guaranteed Mexicans living in the purchased
territories the right to become U.S. citizens), and striking out Article
X (which conceded the legitimacy of land grants made by the Mexican government).
On May 26, 1848, when the two countries exchanged ratifications of the
treaty of Guadalupe Hidalgo, they further agreed to a three-article protocol
(known as the Protocol of Querétaro) to explain the amendments.
The first article claimed that the original Article IX of the treaty, although
replaced by Article III of the Treaty of Louisiana, would still confer
the rights delineated in Article IX. The second article confirmed the legitimacy
of land grants under Mexican law. The protocol was signed in the city of
Querétaro by A. H. Sevier, Nathan Clifford, and Luis de la Rosa.
|Jefferson Davis introduced an amendment giving the U.S.
most of northeastern Mexico, which failed 44–11. It was supported by both
senators from Texas (Sam Houston and Thomas Jefferson Rusk), Daniel S.
Dickinson of New York, Stephen A. Douglas of Illinois, Edward A. Hannegan
of Indiana, and one each from Alabama, Florida, Mississippi, Ohio, Missouri,
and Tennessee. Most of the leaders of the Democratic party, Thomas Hart
Benton, John C. Calhoun, Herschel V. Johnson, Lewis Cass, James Murray
Mason of Virginia, and Ambrose Hundley Sevier, were opposed. An amendment
by Whig Senator George Edmund Badger of North Carolina to exclude New Mexico
and California lost 35–15, with three Southern Whigs voting with the Democrats.
Daniel Webster was bitter that four New England senators made deciding
votes for acquiring the new territories.
The acquired lands west of the Rio Grande are traditionally
called the Mexican Cession in the U.S., as opposed to the Texas Annexation
two years earlier, though division of New Mexico down the middle at the
Rio Grande never had any basis either in control or Mexican boundaries.
Mexico never recognized the independence of Texas prior to the war, and
did not cede its claim to territory north of the Rio Grande or Gila River
until this treaty.
Prior to ratifying the treaty, the U.S. Senate made two
modifications, changing the wording of
Mexican territorial claims relinquished in
the Treaty of Guadalupe Hidalgo in white.
Article XI offered a potential benefit to Mexico in that
the US pledged to suppress the Comanche and Apache raids that had ravaged
northern Mexico. However, the Indian raids did not cease for several decades
after the treaty, although a cholera epidemic reduced the numbers of the
Comanche in 1849.
unnecessarily and unconstitutionally begun by the President
of the United States." This criticism, in which Congressman Abraham Lincoln
played an important role with his Spot Resolutions, followed congressional
scrutiny of the war's beginnings, including factual challenges to claims
made by President Polk. The vote followed party lines, with all Whigs supporting
the amendment. Lincoln's attack won luke-warm support from fellow Whigs
in Illinois but was harshly counter-attacked by Democrats, who rallied
pro-war sentiments in Illinois; Lincoln's Spot resolutions haunted his
future campaigns in the heavily Democratic state of Illinois, and was cited
by enemies well into his presidency.
American occupation of Mexico City
|Mexican territory, prior to the secession of Texas, comprised
almost 1,700,000 sq mi (4,400,000 km2), which was reduced to just under
800,000 by 1848. Another 32,000 were sold to the U.S. in the Gadsden Purchase
of 1853, for a total reduction of more than 55%, or 900,000 square miles.
The annexed territories, comparable in size to Western Europe, were essentially
unsettled, containing about 1,000 Mexican families in Alta California and
7,000 in Nuevo México, as well as large Native
American nations such as the Navajo, Hopi, and dozens of others. A few
relocated further south in Mexico; the great majority remained in the U.S.
Descendants of these Mexican families have risen to prominence in American
life, such as United States Secretary of the Interior Ken Salazar, and
his brother, U.S. Rep. John Salazar, both from Colorado.
A month before the end of the war, Polk was criticized
in a United States House of Representatives amendment to a bill praising
Major General Zachary Taylor for "a war
In much of the U.S., victory and the acquisition of new
land brought a surge of patriotism. Victory seemed to fulfill Democrats'
belief in their country's Manifest Destiny. While Whig Ralph Waldo Emerson
rejected war "as a means of achieving America's destiny," he accepted that
"most of the great results of history are brought about by discreditable
means." Although the Whigs had opposed the war, they made Zachary Taylor
their presidential candidate in the election of 1848, praising his military
performance while muting their criticism of the war.
Many of the military leaders on both sides of the American
Civil War had fought as junior officers in Mexico, including Ulysses S.
Grant, George B. McClellan, Ambrose Burnside, Stonewall Jackson, James
Longstreet, George Meade, Robert E. Lee, and the future Confederate President
In Mexico City's Chapultepec Park, the Monument to the
Heroic Cadets commemorates the heroic sacrifice of six teenaged military
cadets who fought to their deaths rather than surrender to American troops
during the Battle of Chapultepec Castle on September 18, 1847. The monument
is an important patriotic site in Mexico. On March 5, 1947, nearly one
hundred years after the battle, U.S. President Harry S. Truman placed a
wreath at the monument and stood for a moment of silence.
Grant's views on the war
President Ulysses S. Grant, who as a young army lieutenant
had served in Mexico under General Taylor, recalled in his Memoirs, published
in 1885, that:
Generally, the officers of the army
were indifferent whether the annexation was consummated or not; but not
so all of them. For myself, I was bitterly opposed to the measure, and
to this day regard the war, which resulted, as one of the most unjust ever
waged by a stronger against a weaker nation. It was an instance of a republic
following the bad example of European monarchies, in not considering justice
in their desire to acquire additional territory.
Grant also expressed the view that the war against Mexico
had brought punishment on the United States in the form of the American
The Southern rebellion was largely
the outgrowth of the Mexican war. Nations, like individuals, are punished
for their transgressions. We got our punishment in the most sanguinary
and expensive war of modern times.
On the American side, the war was fought by regiments
of regulars and various regiments, battalions, and companies of volunteers
from the different states of the union and the Americans and some of the
Mexicans in the territory of California and New Mexico. On the West Coast,
the U.S. Navy fielded a battalion in an attempt to recapture Los Angeles.
At the beginning of the war, the U.S. Army had eight regiments
of infantry (three battalions), four artillery regiments and three mounted
regiments (two dragoons, one of mounted rifles). These regiments were supplemented
by 10 new regiments (nine of infantry and one of cavalry) raised for one
year's service (new regiments raised for one year according to act of Congress
Feb. 11, 1847).
State Volunteers were raised in various sized units and
for various periods of time, mostly for one year. Later some were raised
for the duration of the war as it became clear it was going to last longer
than a year.
U.S. soldiers' memoirs describe cases of looting
and murder of Mexican civilians, mostly by State Volunteers. One officer's
|We reached Burrita about 5 pm, many of the Louisiana
volunteers were there, a lawless drunken rabble. They had driven away the
inhabitants, taken possession of their houses, and were emulating each
other in making beasts of themselves.
John L. O'Sullivan, a vocal proponent of Manifest
Destiny, later recollected:
|The regulars regarded the volunteers with importance
and contempt ... [The volunteers] robbed Mexicans of their cattle and corn,
stole their fences for firewood, got drunk, and killed several inoffensive
inhabitants of the town in the streets.
Many of the volunteers were unwanted and considered poor
soldiers. The expression "Just like Gaines's army" came to refer to something
useless, the phrase having originated when a group of untrained and unwilling
Louisiana troops were rejected and sent back by Gen. Taylor at the beginning
of the war.
The last surviving U.S. veteran of the conflict, Owen
Thomas Edgar, died on September 3, 1929, at age 98.
1,563 U.S. soldiers are buried in the Mexico City National
Cemetery, which is maintained by the American Battle Monuments Commission.
At the beginning of the war, Mexican forces were divided
between the permanent forces (permanentes) and the active militiamen (activos).
The permanent forces consisted of 12 regiments of infantry (of two battalions
each), three brigades of artillery, eight regiments of cavalry, one separate
squadron and a brigade of dragoons. The militia amounted to nine infantry
and six cavalry regiments. In the northern territories of Mexico, presidial
companies (presidiales) protected the scattered settlements there.
One of the contributing factors to loss of the war by
Mexico was the inferiority of their weapons. The Mexican army was using
British muskets (e.g. Brown Bess) from the Napoleonic Wars. In contrast
to the aging Mexican standard-issue infantry weapon, some U.S. troops had
the latest U.S.-manufactured breech-loading Hall rifles and Model 1841
percussion rifles. In the later stages of the war, U.S. cavalry and officers
were issued Colt Walker revolvers, of which the U.S. Army had ordered 1,000
in 1846. Throughout the war, the superiority of the U.S. artillery often
carried the day.
Political divisions inside Mexico were another factor
in the U.S. victory. Inside Mexico, the centralistas and republicans vied
for power, and at times these two factions inside Mexico's military fought
each other rather than the invading American army. Another faction called
the monarchists, whose members wanted to install a monarch (some even advocated
rejoining Spain), further complicated matters. This third faction would
rise to predominance in the period of the French intervention in Mexico.
The ease of the American landing at Vera Cruz was in large part due to
civil warfare in Mexico City, which made any real defense of the port city
impossible. As Gen. Santa Anna said, "However shameful it may be to admit
this, we have brought this disgraceful tragedy upon ourselves through our
Saint Patrick's Battalion (San Patricios) was a group
of several hundred immigrant soldiers, the majority Irish, who deserted
the U.S. Army because of ill-treatment or sympathetic leanings to fellow
Mexican Catholics. They joined the Mexican army. Most were killed in the
Battle of Churubusco; about 100 were captured by the U.S. and roughly ½
were hanged as deserters. The leader, John Riley, was merely branded since
he had deserted prior to the start of the war.
Impact of the war in the U.S.
As late as 1880, the "Republican Campaign Textbook" by the
Republican Congressional Committee described the war as "Feculent, reeking
Corruption" and "one of the darkest scenes in our history — a war forced
upon our and the Mexican people by the high-handed usurpations of Pres't
Polk in pursuit of territorial aggrandizement of the slave oligarchy."
|Despite initial objections from the Whigs and abolitionists,
the war would nevertheless unite the U.S. in a common cause and was fought
almost entirely by volunteers. The army swelled from just over 6,000 to
more than 115,000. Of these, approximately 1.5% were killed in the fighting
and nearly 10% died of disease; another 12% were wounded or discharged
because of disease, or both.
For years afterward, veterans continued to suffer from
the debilitating diseases contracted during the campaigns. The casualty
rate was thus easily over 25% for the 17 months of the war; the total casualties
may have reached 35–40% if later injury- and disease-related deaths are
added. In this respect, the war was proportionately the most deadly in
American military history.
During the war, political quarrels in the U.S. arose regarding
the disposition of conquered Mexico. A brief "All-Mexico" movement urged
annexation of the entire territory. Veterans of the war who had seen Mexico
at first hand were unenthusiastic. Anti-slavery elements opposed that position
and fought for the exclusion of slavery from any territory absorbed by
the U.S. In 1847 the House of Representatives passed the Wilmot Proviso,
stipulating that none of the territory acquired should be open to slavery.
The Senate avoided the issue, and a late attempt to add it to the Treaty
of Guadalupe Hidalgo was defeated.
The Treaty of Guadalupe Hidalgo was the result of Nicholas
Trist's unauthorized negotiations. It was approved by the U.S. Senate on
March 10, 1848, and ratified by the Mexican Congress on May 25. Mexico's
cession of Alta California and Nuevo México and its recognition
of U.S. sovereignty over all of Texas north of the Rio Grande formalized
the addition of 1.2 million square miles (3.1 million km2) of territory
to the United States. In return the U.S. agreed to pay $15 million and
assumed the claims of its citizens against Mexico. A final territorial
adjustment between Mexico and the U.S. was made by the Gadsden Purchase
"An Available Candidate:
The One Qualification for a
Political cartoon about the 1848
presidential election which
refers to Zachary Taylor or
Winfield Scott, the two leading
contenders for the Whig Party
nomination in the aftermath
Published by Nathaniel Currier
in 1848, digitally restored.
The war was one of the most decisive events for the U.S.
in the first half of the 19th century. While it marked a significant waypoint
for the nation as a growing military power, it also served as a milestone
especially within the U.S. narrative of Manifest Destiny. The resultant
territorial gains set in motion many of the defining trends in American
19th-century history, particularly for the American West. The war did not
resolve the issue of slavery in the U.S. but rather in many ways inflamed
it, as potential westward expansion of the institution took an increasingly
central and heated theme in national debates preceding the American Civil
War. Furthermore, in doing much to extend the nation from coast to coast,
the Mexican–American War was one step in the massive migrations to the
West of Americans, which culminated in transcontinental railroads and the
Indian wars later in the same century.