The Mexican War and
Expansionism
Greed, Manifest Destiny or Inevitability?
Americans Before the Civil War
What Were They Really Like?
• In April 1841, John Tyler inherited the
presidency from William Henry Harrison who
had contracted pneumonia and died a month
after his inauguration.
• William Henry Harrison had been a Whig and
President John Tyler was a Democrat.
• After the victory of Whig William Henry
Harrison in the 1840 election the Whig party
anticipated re-chartering a federal bank, raising
the tariff, and carrying out other nationalist
measures.
• After Tyler became president, true to his
state’s rights principles he vetoed the bank bill.
• The entire cabinet except for Daniel Webster
resigned in protest and Tyler and the Whig
leaders in Congress remained stalemated.
• Tyler fared better in foreign affairs. He and
Secretary of State Daniel Webster managed to
negotiate the 1842 Webster-Ashburton Treaty
that settled and American-Canadian border
dispute.
• The United States also agreed to join Britain in
supporting a naval squadron stationed off the
African coast to capture slave ships attempting
to bring slaves to the Americas.
• President Tyler also settled the Oregon
dispute. Many Americans insisted that the
United States rightfully owned all of the
Oregon country. Tyler offered to divide
Oregon with the British at the 49th parallel. He
offered the British San Francisco, which they
declined.
• President Tyler’s major foreign policy success
came in Texas.
• Americans had crossed into the Spanish-held
territory of Texas early in the 19th century.
• In 1820, the newly independent Mexican
Republic gave Moses Austin a land grant and
the right to settle 300 American families as
permanent citizens.
• In 1823 Stephen Austin, Moses’ son,
established the first American colony in east
Texas.
• By 1825 there were 1,800 colonists, including
443 slaves.
• By 1835, about 20,000 transplanted Americans
were living in Texas.
• There were tensions between Americans and
Mexicans. The Americans were mostly
Protestant and resented the efforts of Mexican
officials to convert them to the Catholic faith.
• Most of them were southerners determined to
grow cotton with slave labor and they resisted
Mexican laws forbidding slavery.
• Many transplanted American felt Mexicans
were culturally or racially inferior.
• Despite these feelings, American settlers in
Texas proved loyal to Mexico.
• Many Americans regretted the surrender of
Texas to Spain in the Adams-Onis Treaty of
1819. The United States tried to buy Texas
back, but failed.
• The Mexican government produced constant
changes of policy and turmoil.
• Matters came to a head under the presidency of
Antonio Lopez de Santa Anna.
• In 1835 Santa Anna marched north with his
army to punish the Texans. Challenging him
were 187 Texans at the Alamo, an adobe
walled former mission in San Antonio, Texas.
• In late February 1836, Santa Anna and 4,000
troops arrived at San Antonio and surrounded
the American force. On March 6, the Mexicans
overwhelmed the Americans who were all
killed.
• Texas declared its independence and named
Sam Houston commander in chief of the Texas
Army. It created a constitution that recognized
slavery and granted each citizen land.
• On April 26, 1836, Sam Houston and his
troops attacked the Mexicans at San Jacinto
and decisively defeated them.
• Texas proclaimed itself an independent
republic.
• As soon as Texas achieved its independence it
sought to be admitted to the United States.
• Americans were divided over the admission to
Texas to the Union. Whigs traditionally
opposed expansion and many northerners
feared that Texas would enter the Union as a
slave state.
• Early in 1837, just before he left office
President Jackson had granted diplomatic
recognition to the Texas Republic.
• For the next few years Texas functioned as a
Republic. Texas or the Lone Star Republic,
began to negotiate with France and Britain
which alarmed Americans.
• President John Tyler finally signed the joint
resolution for Texas to join the union in the
last hours of his administration. Texas entered
the Union as a slave state in December 1845,
but only after another heated debate in
Congress with anti-slavery Whigs leading the
opposition.
The Causes of the Mexican War
1846-1848
• There are different theories about the
origins of the Mexican War. Illinois
Congressman Abraham Lincoln thought
the war as naked United States
aggression against a weaker neighbor.
• Writers like Henry David Thoreau saw it as a
southern slave holders plot.
• Some scholars view the war as an expression
of manifest destiny or American cultural,
political, and racial superiority over the
American continent.
• Mexican scholars see the war as a result of
America’s greed and blatant aggression.
• Another school of interpretation sees the war
as inevitable American expansion of history
and geography.
• The Mexican government had threatened to
retaliate against the United States if it absorbed
Texas.
• The new president, James K. Polk, had
expansionist territorial goals but he did not
want to go to war to achieve them.
• President Polk proposed a settlement of the
Oregon question that had dragged on since the
days of John Quincy Adams a generation
before. Finally, in June 1846 the Oregon
question was settled.
• The United States-Canadian boundary
extended beyond the Great Lakes along the
forty-ninth parallel to the Pacific and all of
Vancouver Island would remain British.
• By the time the Senate approved the Oregon
treaty, Americans and Mexicans were killing
each other along the entire border from Texas
to California.
The Slidell Mission
• In the fall of 1845, President James K. Polk
sent John Slidell to Mexico on a diplomatic
mission.
• Slidell was to say that if Mexico recognized
the Rio Grande as the southwestern boundary
of Texas, the United States would pay the
$3.25 million that Mexico owed to American
citizens as compensation for disorders and
defaults in Mexico.
• Slidell was authorized to offer another $5
million for New Mexico and $25 million for
California. President Polk told Slidell that if
these negotiations failed, he would ask
Congress “to provide proper remedies,” which
most likely was a threat of war.
• The president of Mexico was inclined to
negotiate, but news of Slidell’s mission leaked
out and the Mexico public opinion was hostile.
• Slidell was permitted to enter Mexico but was
not allowed to present his proposals.
• Shortly after Slidell arrived in Mexico, the
Federalist Herrera government fell and the new
Centralist administration sought to pursue a
war. New president Mariano Paredes began to
negotiate with Great Britain for support against
the United States if it came.
• President Polk ordered General Zachary
Taylor to move his troops to the north bank of
the Rio Grande to occupy the disputed Texas
border region and protect Texas against
possible attack.
• By the spring of 1846 both President Polk and
the Americans and the Mexican president and
people concluded that war was inevitable.
• The Mexicans were confident that Britain
would support them, that New England and
abolitionist opposition would hamper the war
effort, and that the Mexicans man for man,
were better soldiers than the Americans.
• On April 23, 1846, President Paredes
announced that Mexico had declared
“defensive war” on the United States.
• Mexican troops crossed the Rio Grande and
attacked a unit of General Zachary Taylor’s
army. In May 1846, President Polk’s war
message was read to Congress and the Senate
declared war by a vote of 40-1 and the House
by a vote of 174-14.
• Young American men flocked to recruiting
offices and the combination of a small regular
army and a mass of volunteers worked well.
• The country enjoyed excellent wartime morale.
• It also enjoyed skilled military leadership, with
a group of well trained officer from West
Point.
• Zachary Taylor and his troops took much
Mexican territory such as Matamoras and
Monterrey.
Conquest of California
• In 1845 President Polk had secretly authorized
the American consul in the California capital
to help stir up a secessionist movement.
• In the meantime a group of Americans had
proclaimed the Republic of California and
Captain John C. Fremont arrived in California
with a contingent of American troops. On July
1, Fremont occupied the Mexican fort at San
Francisco while the Mexican government fled
to Los Angeles.
• All of southern California was in Mexican
hands when Stephen Kearny arrived outside of
San Diego with his small force of men. He and
Robert Stockton and their forces retook
southern California and joined with Fremont.
On January 13, the Mexican forces signed the
Capitulation of Cahuenga and the province of
California was now American.
• Zachary Taylor and Winfield Scott occupied
Mexico and captured Mexico City. Finally
Santa Anna fled, leaving the surrender and
peace negotiations to the ad interim president,
Pedro Anaya.
• On February 2, 1848, Mexico signed the
Treaty of Guadalupe Hildago with the United
States.
• The Treaty gave the United States the
provinces of California and New Mexico.
• The Treaty of Guadalupe Hidalgo confirmed
the Rio Grande as the southwestern boundary
of Texas.
• The Mexican Cession included the present
states of California, Nevada, and Utah, and
parts of Arizona, New Mexico, Wyoming, and
Colorado.
• In return, the United States agreed to pay
Mexico $15 and to assume the $3.5 million of
American citizens’ claims against the Mexican
government.
• The Mexican War lasted almost two years and
cost 13,000 American lives and $100 million.
• The Mexican War was the last phase of
continental expansion that extended the
country to the Pacific Ocean. The Mexican
War added 530,000 square miles to the United
States.
• The settlement of the Oregon boundary dispute
with Great Britain added another 258,000
square miles.
Americans Before the Civil War
What Were They Really Like?
The Moving Frontier
• Generations of American scholars have seen
the west as the key to the American character
and institutions.
• After 1815, the West or the region beyond the
Appalachians, was the fastest growing part of
the United States.
• During this time the west became the home of
15 million Americans.
• At the beginning of the Civil War, American
have over 31 million people and half of them
lived in states and territories where white
communities had not existed when General
George Washington was inaugurated.
• Americans generally moved west along lines
of latitude.
• Indians were continually pushed westward
ahead of the flood of white and black settlers.
The Migrants’ Motives
• Some people were the “loners” who could not
stay put once they had seen the smoke of their
neighbor’s fire.
• Some were refugees fleeing the law, their
creditors, their spouses, their pasts.
• Some followed spouses and parents.
• Many single women thought of the west as the
land of opportunity and emigrated there.
• Economic considerations called most people
West.
• Historian Frederick Jackson Turner believed
that the west transformed immigrants and was
“productive of individualism…”
• He thought the west discouraged governmental
control and was egalitarian. The west was also
free of materialism, according to Turner.
• Turners agreeable, positive picture of the West
is an overstatement. Real westerners were
crude, more materialistic, and less egalitarian
and individualistic in their behavior than
Turner claimed.
Problems of Urbanization
• In 1800 only five towns in America had over
10,000 people- New York, Philadelphia,
Boston, Charleston and Baltimore.
• As the economy changed and grew, new
factories and mills attracted many people to
the older towns and created new ones.
• Housing was a major urban problem and never
adequately solved.
• As well as poor housing, cities were plagued
with the ills of poor water supply, poor waste
disposal and poor health services.
• Crime and violence were also social ills that
increased with urbanization.
• Between 1830 and 1860 violent confrontations
between immigrant Catholics and militant
native Protestants took place in American
cities.
Immigration
• During the 50 years after the Revolution,
immigration to American from Europe had
been light.
• Then in the 1830s, the number of new
immigrants in America grew to almost
600,000. In the 1840s, it grew to 1.7 million
and in the 1850s, 2.3 million.
• Most of the immigrants were from Britain,
Germany, and the southern part of Ireland.
Free Blacks
• Race, even ore than religion and nationality,
challenged America’s egalitarian ideas.
• 200,000 free blacks lived in the northern and
western states in 1850.
• Bigotry harshly affected the life of almost
every free black. They were denied admission
to white schools, refused jobs, and deprived of
basic civil rights.
Women
• America before the Civil War was male
dominated. It was difficult for any woman to
life independently of a man and all of the
professions except teaching were closed to
them.
• Under the law the earnings and property of a
married woman belonged to her husband.
• In a divorce, women usually lost all claim to
their children.
• Women could not hold office or vote.
The Arts in Antebellum America
• Washington Irving and James Fenimore
Cooper produced the first distinguished
national American literature.
• The South produced Edgar Allen Poe and New
England the Transcendentalists, and New
York Herman Melville. Walt Whitman was
also a writer and poet of distinctly American
character.
Reform Movements in America
• Religious Reform
• Temperance
• Women’s Rights
• Anti-Slavery
• Utopian Socialism
Conclusions
• Americans were competitive and
individualistic.
• They were crude, bad-manned, violent and
bigoted.
• They were also humane, romantic, creative,
and socially speculative. They were a people
of paradox.
• Unger says that all changes in America
followed lines of latitude.
• The entire region north of Dixie was in a state
of unusual transition.
• There were antagonisms between East and
West, but Easterners continually moved West
and became like the Westerners they had
deplored.
• By 1860 the Northeast and Northwest
resembled each other more than they did the
South.
• This development of distinctive North-South
sectional identities would soon have
momentous consequences for the American
nation.