Westward Expansion and the Mexican-American War

1. Westward Expansion and the Mexican-American War Unit 6, Lesson 1

2. Essential Idea • The ideal of “Manifest Destiny” inspired Americans to claim the West, which led to the Mexican-American War.

3. Manifest Destiny • Manifest Destiny: • Manifest Destiny—the idea that Americans had a God-given right to conquer and civilize North America • This idea encouraged settlers to move west before, during, and afterthe Civil War

4. Overland Trails • These settlers, called “overlanders,” used routes like the Oregon Trail • Manifest Destiny

5. Moving West • Reasons for Migration: • 1. Economic—some went west for mining, ranching, and farming • “Mountain men” trapped fur and served as guides to settlers • 2. Religious—Mormons, led by Brigham Young, went west to escape religious persecution

6. Frontier Life • Life on the Frontier: • Over time, settlers did increasing damage to the environment • As settler population grew, conflict with Native Americans increased • Settlers dealt with isolation, loneliness, a rugged environment, and Native American attacks

7. Election of 1844 • Election of 1844: • James K. Polk, called the “expansion president,” ran against Henry Clay • Polk’s platform: • 1. Polk was committed to “manifest destiny” and expansion • 2. Polk promised to annex Texas as a new state • 3. Polk promised to acquire California • 4. Polk would end sharing the Oregon Territory with England

8. “Fifty-four Forty or Fight!” • Election Mandate? • Polk won, showing that Americans wanted to expand the country • Polk’s Accomplishments

9. Expansion Begins • Texas: • After Polk’s election, the United States annexed Texas • Consequences: • Annexing Texas angered anti-slavery northerners because it opened new land to slavery • Annexing Texas infuriated Mexico, which felt Texas was really theirs • Tension between the United States and Mexico rose

10. Oregon Treaty • Oregon: • “Fifty-four Forty or Fight!”—this slogan stated the desire of Americans to own ALL of the Oregon Territory up to the 54° 40’ latitude line • However, Polk did not want war with both Mexico AND England • Oregon Treaty—the United States agreed to split the Oregon Territory with England at the 49° line (not 54°40’) • Consequences: • War with England was avoided • Northerners were upset that more land for future free states was not obtained, especially after Texas had been annexed • Manifest Destiny and Oregon

11. The Mexican-American War: Causes • Causes: • 1. Annexing Texas • Mexico never fully recognized Texas independence • Many Mexicans felt that the United States had “stolen” Texas • 2. Desire for California • Polk offered to buy California (and New Mexico) from Mexico • Mexico, angry, refused to even negotiate, raising tension

12. The Mexican-American War: Causes • 3. Texas Border Dispute • Mexico said the Texas/Mexico border started at the Nueces River, the United States said it started at the Rio Grande River • Both countries claimed the land between these two borders

13. The Spark of War Ignited • War Ignites: • Polk ordered troops to march into the disputed territory • The Mexican army attacked and killed 11 of the soldiers • Polk claimed American blood was shed on American soil • Congress declared war on Mexico

14. Opposition to War • Opposition to War with Mexico: • Many northerners and abolitionists opposed the war as a conspiracy to create new future slave states • Wilmot Proviso: • Wilmot Proviso—to appease northerners, this suggested making all land won from Mexico FREE • Pro-slavery congressmen made sure the Wilmot Proviso never passed

15. The Mexican-American War: The Strategy • Part 1: • Capture Santa Fe in New Mexico • What Happened: • Santa Fe was a trade center for northern Mexico • Capturing it cut much of northern Mexico from its southern capital, Mexico City

16. The Mexican American War: The Strategy • Part 2: • Capture California • What Happened: • “Bear Flag Revolt”—California, like Texas, was fighting for independence from Mexico • American troops helped free California • Mexico lost control of its northern half

17. The Mexican-American War: The Strategy • Part 3: • Invade from North • What Happened: • Troops crossed the Rio Grande and invaded south toward Mexico City • Mexican troops left Mexico City unguarded to intercept American troops

18. The Mexican-American War: The Strategy • Part 4: • Capture Mexico City • What Happened: • General Winfield Scott took troops and captured Mexico City • With the northern half of Mexico gone and the capital captured, Mexico had to surrender

19. The Mexican-American War Ends • Terms of Peace: • Treaty of Guadalupe Hidalgo—in this peace treaty, sold its northern half to the United States and recognized the Rio Grande as the Texas border • Polk and Expansion (Watch first 2:40) • Mexican Cession—this land made up what is now the American Southwest