Mexican–American War was an armed conflict between
States and Mexico from 1846 to
1848 in the wake of the 1845 U.S. annexation of Texas.
ownership of Texas as a breakaway province and refused to recognize
and subsequent military
victory by Texas in 1836.
In the U.S. the conflict is often referred to simply as the
and sometimes as the
. In Mexico, terms for it include
Intervención Estadounidense en México
intervention in Mexico), Invasión Estadounidense de México
(American Invasion of Mexico), and Guerra del 47
consequence of the war was the Mexican
Cession of the territories of Alta California and Santa
Fe de Nuevo México to the United States under the Treaty of Guadalupe
Hidalgo. In addition, Mexico accepted the loss of
Texas and the Rio
1835, President Andrew Jackson
developed a "passion" to acquire all Mexican territory north of the
37th parallel north after a navy
purser's favorable report on the San Francisco Bay Area, and issued instructions to pursue this, but the
suggestion came to nothing.
In 1842, the American minister in
Mexico Waddy Thompson, Jr.
to Daniel Webster
, "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."Expansion on the Pacific coast was foremost
in the minds of President Polk and his associates in their whole
conduct of the war.
Republic of Texas
immigrants in Texas declared independence from Mexico in 1836, and
in the following years, Texas consolidated its status as an
independent republic by establishing diplomatic ties with Britain, France, and the
Most Texans were in favor of annexation by
the United States, but U.S. President Martin Van Buren
rejected it; then the
pro-independence Mirabeau Lamar
president of Texas 1838-41; then the U.S. Senate rejected an
annexation treaty in 1844.
Under U.S. President John Tyler
was offered admission to the Union as a state via, controversially,
a joint resolution of
rather than a treaty. The bill was signed into law on
March 1, 1845. It was ratified by Texas on July 4. Texas became the
28th state on December 29, a law signed by President James K. Polk
Origins of the war
The Mexican government had long warned the United States that
annexation would mean war. Because the Mexican congress never
recognized Texas' independence, it saw Texas as a rebellious
territory that would be retaken in the future. Britain and France, which
recognized the independence of Texas, repeatedly tried to dissuade
Mexico from declaring war.
British efforts to mediate were
fruitless, in part because additional political disputes
(particularly the Oregon
) arose among Mexico, Britain, and the United
States. When Texas was granted statehood in 1845, the Mexican
government broke diplomatic relations with the United States.
The Texan claim to the Rio Grande boundary had been omitted from
the annexation resolution to help secure passage after the
annexation treaty failed in the Senate, but President Polk
nevertheless now claimed the Rio Grande boundary, and this provoked
a dispute with Mexico. In June 1845, James
K. 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
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 in case Mexico
declared war, while staying on good terms with the inhabitants. At
the same time he wrote to Thomas
, the American consul in Monterey, disclaiming American
ambitions but offering to support independence from Mexico or
voluntary accession to the United States, and warning that a
British or French takeover would be opposed.
In the winter of 1845-46, the federally commissioned explorer
John C. Fremont
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 part of California and visited Santa Cruz
and the Salinas Valley
, explaining he was 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
Peak and raising the American flag.
word that his actions were counterproductive. Fremont left
California in March but returned to California and assisted the
in Sonoma, where a number of American immigrants stated
that they were playing “the Texas game” and declared California’s
independence from Mexico.
November 10, 1845, Polk sent John
Slidell, a secret representative, to Mexico City with an offer
of $25 million ($ 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
Polk authorized Slidell to forgive the $3
million ($ today) owed to U.S. citizens for damages caused by the
Mexican War of
and pay another $25 to $30 million ($ to $ today)
in exchange for the two territories.
Mexico was not inclined nor in a position 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 open 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
in order to peacefully negotiate the problem of Texas annexation,
he was accused of treason and deposed. After a more nationalistic
government under General Mariano Paredes y Arrillaga
to power, it publicly reaffirmed Mexico's claim to Texas; Slidell,
convinced that Mexico should be "chastised," returned to the United
Conflict over the Nueces Strip
Polk ordered General Taylor and his forces south to the Rio Grande,
entering the territory that Mexicans claimed as their own.
claimed the Nueces
River — about 150 miles (240 km) north of the
Grande — as its border with Texas; the United States
claimed it was the Rio Grande, citing the 1836 Treaties of Velasco.
however, had never ratified these treaties, which were signed by
was a prisoner in 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,
Mexican forces under General Mariano Arista
prepared for war.
On April 25, 1846, a 2,000-strong Mexican cavalry
detachment attacked a 63-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 11 U.S. soldiers in what later became known as
the Thornton Affair
after the U.S.
officer who was in command. A few survivors were returned to Fort
Brown by the Mexicans, including wounded sent in an
Declaration of war
By then, Polk had received word of the Thornton Affair. This, added
to the Mexican government's rejection of Slidell, Polk believed,
constituted a casus belli
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.” A joint
session of Congress approved the declaration of war on May 13th,
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
. 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
Overview of the war.
Once the United States declared war on Mexico, Antonio Lopez 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 in the past. 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 United States, 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 of these agreements.
Santa Anna declared himself president again and unsuccessfully
tried to fight off the United States invasion.
Opposition to the war
In the United States, increasingly divided by sectional
rivalry, the war was a partisan issue
and a key part of the origins of the American Civil
. Most Whigs
the North and South opposed it; most Democrats supported it.
animated by a popular belief in Manifest Destiny
, supported it in hopes of
adding territory to the South and avoiding being outnumbered by the
faster-growing North. It was John O'Sullivan, the editor of the
"Democratic Review", who 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
growth of a Slave Power
; Whigs generally
wanted to deepen the economy with industrialization, not expand it
with more land. Democrats wanted more land, and northern Democrats
were especially attracted by the possibilities in the far
northwest. Joshua Giddings
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: Fellow Whig Abraham Lincoln
, who had been elected to
Congress several months after the declaration of war, 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:
attacked the war
as an attempt by slave-owners—frequently referred to as "the
" — to expand the grip of
and thus assure their continued
influence in the federal government. Acting on his convictions,
Henry David Thoreau
for his refusal to pay taxes to support the war, and penned his
famous essay, Civil
Former President John Quincy Adams
also expressed his belief that the war was fundamentally an effort
to expand slavery in a speech he gave before the House on May 25,
1846. In response to such concerns, Democratic Congressman David Wilmot
introduced the Wilmot Proviso
, which aimed to prohibit
slavery in any new territory acquired from Mexico. Wilmot's
proposal did not pass Congress, but it spurred further hostility
between the factions.
To end mounting tensions with Britain over Oregon Country
, Polk negotiated a treaty with
Britain that gave the U.S. control of the southern half of
The Siege of Fort Texas
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 and two killed during the
bombardment. Among the dead was Jacob Brown, after whom the fort
was later named.
On May 8, Zachary Taylor arrived with 2,400 troops to relieve the
fort. However, Arista rushed north and intercepted him with a force
of 3,400 at Palo Alto
Americans employed "flying artillery," the American term for
, 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
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 vicious 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 unknown
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 further 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
cavalry force under Stephen W.
Kearny to invade western Mexico from
Leavenworth, reinforced by a Pacific fleet under John D. Sloat
. This was done primarily because of
concerns that Britain might also attempt to occupy 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 Monterrey.
Although the United States declared war against Mexico on May 13,
1846, it took almost two months (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 keep peace between the States and the small
Mexican military garrison commanded by José Castro
. U.S. Army captain John C. Frémont, with about sixty well-armed
men, had entered California in December, 1845, and was marching
slowly to Oregon when he
received word that war between Mexico and the U.S. was imminent and
so began his chapter of the war, the "Bear Flag
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, "California
John Drake Sloat, upon hearing of
imminent war and the revolt in Sonoma, ordered his naval and marine
forces to occupy Yerba Buena (present-day San Francisco) on July 7 and raise the
flag of the United States; this was accomplished 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.
Alta California (the present-day American state of
California), Mexican General José
Castro and Governor Pío Pico fled
southward into still-loyal Mexico.
Stockton's forces, sailing southward to San Diego, stopped in San
Pedro, he sent fifty U.S.
Marines ashore; this force entered Los Angeles unresisted on August 13, 1846.
success of this so-called "Siege of
", the nearly bloodless conquest of California
Stockton, however, left too small a force in Los Angeles, and the
, 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
, U.S.N., were
repulsed in the Battle of
, fought from October 7 through October 9,
1846, near San Pedro
Meanwhile, General Stephen W.
Kearny, with a squadron of 139 dragoons that he had led on a grueling march across
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 were
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
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 now totalling 607 soldiers and marines fought and defeated a
force of about 300 men under the command of
Captain-general Flores in the decisive Battle of Rio San Gabriel
next day, January 9, 1847, the Americans fought and won the
Battle of La Mesa
. On January 12,
the last significant body of Californios
U.S. forces. That marked the end of armed resistance in California,
and the Treaty of Cahuenga
signed the next day, on January 13, 1847.
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 United States. 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.
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
. A U.S. infantry division and the Texas Rangers
captured four hills to the west of the town and with them heavy
cannon. That lent the U.S. soldiers the strength to storm the city
from the west and east. Once in the city, U.S. soldiers fought
house to house: each was cleared by throwing lighted shells, which
worked like grenades.
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 some U.S. troops
were routed, but were saved by artillery fire against a Mexican
advance at close range by Captain Braxton
, and a charge by the mounted Mississippi Riflemen under
. Having suffered
discouraging losses and having word of upheaval in Mexico City,
Santa Anna withdrew that night, leaving Taylor in control 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
1, 1847, Alexander William 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 Press and Popular War Enthusiasm in the United States
During the war, inventions such as the telegraph created new
communication ways 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” as it
was called, was able to realize the voracious need of the public to
get the astounding war news. This was the very first time in the
American history where the accounts by journalists, instead of the
opinions of politicians, caused great influence in shaping people’s
minds and attitudes towards a war. At all times, news about the war
caused extraordinary popular excitement.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 presidential candidates.
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 home village.
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 in order
to join another U.S. unit and get a second enlistment bonus. Others
deserted because of the miserable conditions in camp, or using the
army to get free transportation to California, where they deserted
to join the gold rush.
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 the San
, 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 —threatening to kill
them if they failed to comply. The generous promises proved
illusory for most deserters, who risked getting shot if captured by
U.S. forces. Indeed, about fifty of the San Patricios were tried
and hanged following their capture at Churubusco in August
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
Scott performed the first major amphibious
landing in the history of the United States 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. Included in the
invading force were Robert E. Lee
, George Meade
Ulysses S. Grant
, and Thomas
. The city was defended by Mexican General
Juan Morales with 3,400 men. Mortars
and naval guns under Commodore Matthew
were used to reduce
the city walls and harass defenders. The city replied as best as 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
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
, of Scott's 3rd Infantry, reflected on the resistance of
the Mexican army:
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.
City was laid open in the Battle of Chapultepec and subsequently occupied. Winfield Scott became an American national
hero after his victories in the Mexican–American War, and later
became military governor of occupied Mexico City.
Treaty of Guadalupe Hidalgo
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
, signed on February 2, 1848 by American diplomat
and Mexican plenipotentiary
representatives Luis G.
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, and parts
of Colorado, Arizona, New
Mexico, and Wyoming.
In return, Mexico received US $
18,250,000 ($ 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
$3.25 million ($ today) in debts that the Mexican government owed
to U.S. citizens. The acquisition was a source of controversy at
the time, especially among U.S. politicians who had opposed the war
from the start. A leading antiwar U.S. newspaper, the Whig
sardonically concluded that:Jefferson Davis
introduced an amendment
giving the U.S. most of northeastern
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
, James Murray Mason
Virginia, and Ambrose Hundley
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
acquired lands west of the Rio Grande are traditionally called the Mexican Cession in the United States, 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 actual control or in Mexican boundaries.
Mexico never recognized the independence of Texas prior to the war,
and did not cede 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 language of 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 pursuant to Mexican law. The protocol was
signed in the city of Querétaro by A. H. Sevier, Nathan Clifford
and Luis de la Rosa.
Mexico lost more than 500,000 square miles (about
1,300,000 km²) of land, 55% of its national territory. This
figure rises to over two thirds of its territory if Texas is
included. The annexed territories contained about 1,000 Mexican
families in Alta California and 7,000 in Nuevo México. A few
relocated further south in Mexico; the great majority remained in
the United States. Descendants of these Mexican families have risen
to prominence in American life, such as United States Secretary
of the Interior Ken Salazar
, and his
Salazar, both from Colorado.
A month before the end of the war, Polk was criticized in a
House of Representatives
amendment to a bill praising Major General Zachary Taylor
for "a war unnecessarily and
unconstitutionally begun by the President of the United States".
This criticism, in which Congressman
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.
In much of the U.S., victory and the acquisition of new land
brought a surge of patriotism (the country had also acquired the
southern half of the Oregon Country
in 1846 through a treaty with Great Britain). Victory seemed to
fulfill citizens' 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
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
, George B. McClellan
, Ambrose Burnside
, Stonewall Jackson
, James Longstreet
, George Meade
, and Robert E. Lee
well as the future Confederate
President Jefferson Davis
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
General Ulysses S. 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
in 1885, that:
Grant also expressed the view that the war against Mexico had
's punishment on the United States in
the form of the American Civil
On the American side, the war was fought by regulars and
volunteers, with the majority of atrocities committed by the
volunteers. U.S. soldiers' memoirs describe cases of scalping
innocent civilians, the rape and murder of women, the murder of
children, the burning of homes, and the desecrating of Catholic
religious objects and buildings. One
officer's diary records:John L.
, a vocal proponent of
Manifest Destiny, later recollected: 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 General Taylor at the
beginning of the war.
One of the contributing factors to loss of the war by Mexico was
the inferiority of their weapons. The Mexican army was using
(e.g. Brown Bess
) from the Napoleonic Wars
; furthermore, Mexican troops
were trained to fire with their muskets held loosely at hip-level,
while U.S. soldiers used the more accurate method of butting the
rifle up to the shoulder and taking aim along the barrel. 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
Political divisions inside Mexico were another factor in the U.S.
victory. Inside Mexico, the centralistas
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
(some even advocated rejoining Spain)
further complicated matters. This third faction would rise to
predominance in the period of the French intervention in
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
half were hanged as deserters.
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
Impact of the war in the United States
Despite initial objections from the Whigs and abolitionists, the
war would nevertheless unite the United States 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 this total, approximately
1.5% were killed in the fighting, and nearly 10% died of disease;
another 12% were wounded or discharged because of disease, or
For years afterward, Mexican–American War 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
During the war, political quarrels in the U.S. arose regarding the
disposition of conquered Mexico. A strong "All-Mexico" movement
annexation of the entire territory. Veterans of the war who had
seen Mexico first hand were unenthusiastic and anti-slavery
elements opposed that position and fought for the exclusion of
slavery from any territory absorbed by the United States. 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
was the result of Nicholas
'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 United States
agreed to pay $15 million and assumed the claims of its citizens
against Mexico. A final territorial adjustment between Mexico and
the United States was made by the Gadsden Purchase
As late as 1880, the "Republican Campaign Textbook" by the Republican Congressional
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
- The term "American" to describe things from the United States
is often frowned upon by many Mexican, Central and South Americans,
because many consider "American" to refer to things from the
Americas, not solely the United States of America. However,
"estadounidense" is often translated to "American" in this context,
although in general, "estadounidense" can be defined as "of the
- De Voto, Bernard, Year of Decision 1846 (1942).
- Mayers, David; Fernández Bravo, Sergio A., "La Guerra Con
Mexico Y Los Disidentes Estadunidenses, 1846-1848" [The War with
Mexico and US Dissenters, 1846-48]. Secuencia [Mexico]
2004 (59): 32-70. Issn: 0186-0348.
- Meed, Douglas. The Mexican War, 1846-1848 (2003). A
- Rodríguez Díaz, María Del Rosario. "Mexico's Vision of Manifest
Destiny During the 1847 War" Journal of Popular Culture
2001 35(2): 41-50. Issn: 0022-3840.
- Smith, Justin Harvey. = The War with Mexico (2 vol
1919), Pulitzer prize vol 2 online.
- Bancroft, H.H. History of California (1888) online.
- Bauer K. Jack. Zachary Taylor: Soldier, Planter, Statesman
of the Old Southwest. Louisiana State University Press,
- Eisenhower, John. So Far From God: The U.S. War
with Mexico, Random House (New York; 1989).
- Frazier, Donald S. The U.S. and Mexico at War,
- Hamilton, Holman, Zachary Taylor: Soldier of the
- Johnson, Timothy D. Winfield Scott: The Quest for Military
Glory, University Press of Kansas (1998).
- Foos, Paul. A Short, Offhand, Killing Affair: Soldiers and
Social Conflict during the Mexican War (2002).
- Lewis, Lloyd. Captain Sam Grant (1950).
- Smith, Justin Harvey. The War with Mexico. 2 vol
(1919). Pulitzer Prize winner. full text online.
- Winders, Richard Price. Mr. Polk's Army Texas A&M
Press (College Station, 1997).
Political and diplomatic
- Albert J. Beveridge; Abraham Lincoln, 1809-1858.
Volume: 1. 1928.
- Brack, Gene M. Mexico Views Manifest Destiny, 1821-1846: An
Essay on the Origins of the Mexican War (1975).
- Fowler, Will. Tornel and Santa Anna: The Writer and the
Caudillo, Mexico, 1795-1853 (2000).
- Gleijeses, Piero. "A Brush with Mexico" Diplomatic
History 2005 29(2): 223-254. Issn: 0145-2096 debates in
Washington before war.
- Graebner, Norman A. Empire on the Pacific: A Study in
American Continental Expansion. (1955).
- Graebner, Norman A. "Lessons of the Mexican War." Pacific
Historical Review 47 (1978): 325-42. in
- Graebner, Norman A. "The Mexican War: A Study in Causation."
Pacific Historical Review 49 (1980): 405-26. in
- Jay, William. A Review of the Causes and Consequences of
the Mexican War. American Peace Society (Boston, 1853).
- Krauze, Enrique. Mexico: Biography of Power, Harpers:
- Pletcher David M. The Diplomacy of Annexation: Texas,
Oregon, and the Mexican War. University of Missouri Press,
- Price, Glenn W. Origins of the War with Mexico: The
Polk-Stockton Intrigue. University of Texas Press, 1967.
- Reeves, Jesse S. "The Treaty of Guadalupe-Hidalgo,"
American Historical Review, Vol. 10, No. 2 (Jan., 1905),
pp. 309–324 in JSTOR.
- Robinson, Cecil, The View From Chapultepec: Mexican Writers
on the Mexican War, University of Arizona Press (Tucson,
- Ruiz, Ramon Eduardo. Triumph and Tragedy: A History of the
Mexican People, Norton 1992.
- Schroeder John H. Mr. Polk's War: American Opposition and
Dissent, 1846-1848. University of Wisconsin Press, 1973.
- Sellers Charles G. James K. Polk: Continentalist,
1843-1846 Princeton University Press, 1966.
- Smith, Justin Harvey. The War with Mexico. 2 vol
(1919). Pulitzer Prize winner. full text online.
- Stephenson, Nathaniel Wright. Texas and the Mexican War: A
Chronicle of Winning the Southwest. Yale University Press
- Weinberg Albert K. Manifest Destiny: A Study of Nationalist
Expansionism in American History Johns Hopkins University
- Yanez, Agustin. Santa Anna: Espectro de una sociedad