THE MEXICAN-AMERICAN WAR,
1846 - 1848
From Origins to Consequences…
OPPONENTS OF THE ANNEXATION OF TEXAS
Mexico:
The most outspoken opponent of the
annexation of Texas was undoubtedly
the sovereign nation of Mexico, which
still considered Texas a part of their
nation.
Anti-Slavery Northerners:
Northerners – especially Whigs, but also
free soil Democrats – opposed the
annexation of Texas as well. This was
largely because they saw in Texas a new
slave state, and perhaps more than one!
THE ISSUE OF SLAVERY DIVIDED THE PARTY
Both Martin Van Buren and Henry Clay
refused to state with any clarity that
they would annex Texas while they were
running for President in 1844. As a
result, they lost out. Van Buren – who
would go on to run for President as a
Free-Soiler – lost out on the Democratic
nomination to “dark horse” candidate
James K. Polk. Clay, meanwhile, would
lose the election. The principle reason:
American favored expansion and
considered it our “Manifest Destiny” to
control the future of the West, including
Texas. Slavery or no slavery!
THE FREE-SOIL PARTY: THE LIBERTY PARTY
When Henry Clay announced that he
would support the annexation of Texas in
on uncertain terms, he lost the support of
a small percentage of his own party, the
Whigs. While it may not have been a
huge number of votes, they were critical
to Clay’s plan for victory. He lost
several states’ electoral college votes
because some of his former supporters
chose to support the Liberty Party –
which opposed slavery and opposed the
annexation of Texas.
“FIFTY-FOUR FORTY OR FIGHT!”
The jingoist campaign slogan of James K.
Polk was “Fifty-Four Forty or Fight!” It was a
direct threat to England, with whom the
United States had peacefully occupied the
Oregon Territory since 1818… Polk
demanded that England cede all territory in
the Oregon Country to the United States,
and threatened war if they did not give up.
Happily, after the war, Polk would ease off
this demand. James Buchanan, his Secretary
of State, would negotiate a treaty with
England in which the US retained the
Southern portion of the Oregon Country, and
the English would retain the northern parts.
PRESIDENT JOHN TYLER OF VIRGINIA
It was President John Tyler of Virginia
who formally annexed Texas in 1845 –
at the tale end of his accidental
Presidency. Tyler insisted that the
boundary between the United States
and Mexico was now the Rio Grande
River. Mexicans insisted that Texas’
border had always been at the Nueces
River, hundreds of miles farther north.
Mexico objected to the annexation of
Texas no matter where the boundary
was – but the Rio Grande as the border
added insult to injury.
THE REBUFFED OFFER OF JOHN SLIDELL
John Slidell was sent to Mexico by
President James K. Polk in order to
acquire California. He offered millions
of dollars for the land – but ever at that,
it was a low-ball offer. (He offered
about $25 Million. At the end of the
Mexican-American War, Mexico would
lose California and all of the Mexican
Cession for just $20 Million.) Polk was
angered that Mexican government
officials refused to meet with Slidell, and
that they imprisoned him when he
refused to leave the country.
GENERAL ZACHARY TAYLOR PROVOKES WAR
James K. Polk essentially gave Zachary
Taylor the order to provoke the
Mexican-American War. Polk ordered
Taylor to march into the disputed
territory between the Nueces River and
the Rio Grande along the border
between Texas and Mexico. Indeed,
Taylor’s men sought out the Mexican
Army. When shots were exchanged,
Polk insisted that this was justification for
war, and went before Congress to seek
a formal declaration.
CONGRESS DECLARED WAR AGAINST
MEXICO IN 1846 – WITH VERY FEW
DISSENTING VOTES.
The Senate voted 40 – 2 in
favor of war with Mexico. The
House of Representatives voted
to declare war 174 – 14.
THE THREE PRONGED
ATTACK ON MEXICO,
1846 - 1848
 The United States invaded Mexico from the
Texas border and moved to the south, taking
Monterrey and Buena Vista rapidly.
 A United States Naval expedition landed at
Veracruz, Mexico and proceeded to attack
Mexico City. Mexico City fell in the autumn of
1847.
 The United States organized an expedition to
seize California from the onset of the war, which
was successful.
FREDERICK DOUGLASS CONDEMNED THE WAR, WHICH
HE BELIEVED WAS WAGED TO SPREAD SLAVERY.
Frederick Douglass believed that the
Mexican-American War was provoke in
order to expand the slave territory of the
United States. He sympathized with the
Mexicans for a variety of reasons, not the
least of which was the fact that Mexico had
forbidden slavery throughout their country in
1829 (including in Texas!) When Texas was
annexed, Douglass – along with many
Northerners and free-soilers – feared that
four or more slave states might be carved
from the region. Now, he feared that even
more Mexican land would become slave
territory.
CALIFORNIA’S BEAR FLAG REPUBLIC
Stephen Kearny led a small force
of Americans to seize California,
where John C. Fremont – leader of
an American militia – had already
declared California an
independent republic…
THE TREATY OF
GUADALUPE-HIDALGO
ENDS THE WAR IN 1848
 Mexico ceded over 500,000 square miles of
land including parts of present day New
Mexico, Arizona, Colorado, Wyoming, Nevada,
and California.
 Mexico accepted the boundary between Texas
and Mexico as the Rio Grande River, as the
United States had insisted before the conflict.
 The United States paid Mexico approximately
$18.25 Million for the land and forgave some
Mexican debts owed to Texans.