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
Millions of Americans in 1840s & 50s
believed that God chose Americans to
control of the Western Hemisphere
 Felt mission was to spread democratic institutions
from "sea to shining sea.“
 Land greed and ideals joined into a potent mix for
expansion
 "Manifest destiny" phrase coined in 1844 by John L.
Sullivan
 Movement really began in 1830s with Jackson & Van
Buren removing Indians

Democrats supported "Young Hickory" James K.
Polk
 Sought to annex Texas & gain Oregon up to the 54-40
parallel.

Whigs supported Henry Clay

Liberty Party: 1st party created to block the
extension of slavery
 Candidate: James G. Birney, founder of Kentucky Anti-
Slavery Society
 Party ran in both 1840 and 1844 elections.

Polk d. Clay 170-105 (Clay lost NY by 5K votes)

Polk’s 4-Point
Program
 Lowered the tariff of
1842 from 32% to
25%
 Restoration of the
Independent Treasury
System (1846)
 Acquisition of
California
 Settlement of the
Oregon dispute

Control of the Oregon Territory had been
under dispute for decades
 John Jacob Astor: Developed the American Fur
Company into a huge enterprise organizing the fur
trade from the Great Lakes to Oregon.
 Conflict with Russia
 1812: Russia established Fort Ross just north of San
Francisco
 1820: Monroe Doctrine
 1824-25: Treaties with U.S. & Britain pushed Russia to
54-40’ line
 U.S. & Britain became sole possessors.

1840’s: Flood of American pioneers came to
Oregon on a trail blazed by Jedediah Smith
 Oregon Trail began at Independence, MO or Council
Bluffs, IA
 2,000 mile trail; average of 17 deaths per mile for
pioneers
 1846: 5,000 U.S. settlers lived south of Columbia
River; British had only 700 people living north of river
 Early in 1846, Britain agreed to 49th parallel

1835-1836: American
settlers in Texas fought
the Texas Revolution

1836-1846: They ruled
themselves as the
Republic of Texas
 Mexico refused to
recognize Texan
independence.
 Threatened war if the U.S.
should try to annex the
territory.

Texas was the leading issue in
the Election of 1844
 Opponents feared expansion of
slavery into new region.
 Southerners strongly supported
annexation.

1845: President John Tyler
won a joint resolution in
Congress for annexation

Mexico claimed U.S. had
unjustly taken Texas; refused
to recognize its annexation

Polk wanted to buy California from Mexico
 The Texas issue had caused Mexico to sever
diplomatic relations with U.S.
 Boundary dispute: Original boundary was the
northerly Nueces River; Texans claimed the Rio
Grande to the South
 Polk honored Texas’ boundary & claimed $3 million
in damages
 Polk sent John Slidell to Mexico City in late 1845 to
buy California for $25 million
 Mexico refused to allow Slidell to present his
proposition

January 1846: Polk
ordered General
Zachary Taylor to march
from Nueces River to
Rio Grande, and
ordered Navy in Gulf of
Mexico and California
coast to be ready.
 Polk was prepared to
force a showdown, but
none occurred

April 1846: Mexican troops crossed Rio Grande and
attacked Taylor; 16 casualties
 Polk sent war message to Congress.
 Congress overwhelmingly voted for declaration of war.
 Southern expansionists eager to take more Mexican
territory.
 A majority of Whigs opposed the war in principle.
 Some Whigs questioned if the war had begun on U.S. territory
 Spot Resolutions: Rep. Abraham Lincoln sought the exact "spot“
 Many Whigs believed U.S. had no legal right to land south of Nueces
River.
 Ralph Waldo Emerson feared slavery issue in new conquered
territories would lead to a severe sectional crisis: "Mexico will poison
us!"

California Campaign
 Captain John C. Fremont
captured California, after
the state had earlier won
its independence in the
Bear Flag Revolt
 In 1846, General
Stephen W. Kearny
captured Santa Fe and
moved in to reinforce
California

Pacific Coast Campaign
 Commodore John D. Sloat seized Monterey & San
Francisco.

Mexico Campaign
 General Zachary Taylor was victorious at Monterey
and Buena Vista
 Taylor became an overnight hero (elected president in
1848).
 General Winfield Scott pushed inland from Vera Cruz
and captured Mexico City
 Mexico still refused to negotiate and instead carried
on guerrilla warfare.

Treaty of Guadalupe Hidalgo (1848)
 Provisions:
 U.S. gained California, and modern-day NM, AZ, UT and
NV - ½ of Mexican territory
 U.S. to pay $15 million and assumed claims of U.S.
citizens against Mexico of $3,250,000
 Treaty approved by Senate 38-14 despite bitter
debate
 "Mexican Whigs" disapproved of war & even
threatened to cut off supplies to U.S. forces in Mexico
 Expansionists in South clamored for all of Mexico
 Calhoun pushed for treaty immediately before
significant opposition mounted

Most significantly, slavery issue reignited: Slavery or
not in new the territories?
 In a broad sense, Mexican War resulted in Civil War
 Abolitionists saw Mexican War as conspiracy of
southern slave owners.
 Wilmot Proviso (1848)
 Slavery should never exist in any of territory gained from Mexico
 Twice passed House but not Senate; endorsed by all but 1 free
state
 Southerners resented Northern attempts to prevent expansion
of slavery

U.S. territory increased by 1/3 (including Texas);
bigger than Louisiana Purchase

13,000 Americans dead, mostly by disease.

Sentiment for Manifest Destiny increased in U.S.

Latin America began to negatively view U.S. as the
"Colossus of the North“

U.S. forces experienced in war; would effect scope
of Civil War