the west expansion and the mexican war

1. Westward Expansion and the
Mexican War
HIS 103

2. Trails to the West
 Mexico loosely
controlled northern
provinces
 John Frémont & Kit
Carson explored
Rockies in 1840s
 Oregon Country jointly
ruled by Britain & U.S.
 Buchanan-Pakenham
Treaty (1846) divided
Oregon in half at 49th
parallel
Copyright 2000, Bedford/St. Martin’s Press

3. Manifest Destiny
 Coined by N.Y. journalist John
O’Sullivan in 1845
 Symbolized belief that superior
white, Christian civilization was
destined to rule continent
 Jackson’s Indian removal policy
meant to clear the way for this
 Ft. Laramie Conference (1851)
began process of confining Plains
Indians to reservations American Progress, by
John Gast (1872)

4. The Lone Star Republic
 Adams-Onís Treaty (1819) settled
boundary with Mexico & added Florida
 Mexico permitted American
settlement, 1824-1830
 Organized by empresarios like
Stephen Austin
 20,000 Americans in Texas by 1830
 Gen. Antonio Lopez de Santa Anna
became dictator of Mexico in 1834
 Sam Houston led Texas Revolution
in 1836
 The Alamo (Feb. 23 – March 6,
1836) & Goliad Massacre (March
20) spurred rebels
 Santa Anna captured at San Jacinto
(April 21) & forced to grant Texas
independence
Copyright 2000, Bedford/St. Martin’s Press
The Alamo

5. San Jacinto Monument Antonio Lopez de Santa Anna

6. Annexing Texas
 Jackson tried to buy all of northern Mexico in
1835, but refused to submit annexation treaty
in 1836
 John Quincy Adams staged 3-week
filibuster in 1838 to prevent annexation
 1844 annexation treaty defeated when
Secretary of State John Calhoun explicitly
linked it to defense & expansion of slavery
 Became key issue in 1844 campaign
 James Polk demanded Oregon & Texas
 Henry Clay backpedaled at last minute,
costing him N.Y. & election
 Lame-duck Congress passed joint resolution
annexing Texas in 1845
Sam Houston

7. Polk Provokes a War
 John Slidell sent to Mexico, Dec. 1845
 Offered $25 million for California, New
Mexico & territory north of Rio Grande
 Rejected by resentful Mexican gov’t
 Polk ordered Gen. Zachary Taylor’s
troops to north bank of Rio Grande
 Nueces River was boundary
 Claimed “American blood shed on
American soil”
 Whigs opposed war, but voted to fund
it to show patriotism

8. The Mexican War (1846-1848)
 Taylor’s army won battles
of Monterrey (Sept. 1846) &
Buena Vista (Feb. 1847)
 Winfield Scott led
amphibious invasion that
captured Mexico City in
Sept. 1847
 John Frémont & Stephen
Kearny conquered
California & New Mexico
Copyright 2000, Bedford/St. Martin’s Press

9. Battle of Monterrey (Sept. 1846)

10. Gen. Scott Enters Mexico City

11. The Results
 The cost of war:
 12,876 U.S. soldiers dead
 $98 million
 Junior officers became Civil War generals
 Treaty of Guadeloupe Hidalgo (1848):
 U.S. acquired California, New Mexico & rest
of Texas (over 500,000 square miles)
 75,000 inhabitants would become U.S. citizens
if they chose to stay
 U.S. paid Mexico $15 million & assumed
$3.25 million in U.S. citizens’ claims against
Mexico
Gen. Zachary Taylor
Gen. Winfield Scott

12. War Politicized Slavery Issue
 Wilmot Proviso
 David Wilmot was a Pennsylvania Democrat
 Banned slavery in all territories acquired from
Mexico
 Calhoun Resolutions
 John C. Calhoun argued territories were common
possession of all states & citizens
 Forbidding slave owners to bring slaves into
territories violated 5th Amendment
 Popular Sovereignty
 Lewis Cass was a Michigan Whig turned
Democrat
 Argued each territory should decide slavery issue
for itself
David Wilmot
Lewis Cass