The Mexican-American War and Westward Expansion

Introduction

• The American West is associated with adventure, lawlessness, and opportunity.
• The expansion westward is tied to the Mexican-American War in the mid-19th century.

The United States in the 1840s

• America was a young country eager to expand.
• President James K. Polk was a strong proponent of expansion.
  • Believed in Manifest Destiny: the idea that the U.S. had a duty to expand westward across North America.
• Incentives for American settlers:
  • Spread religion.
  • Strike it rich in business.
  • Start fresh.

Tensions with Mexico

• Mexico was not pleased with America's westward expansion.
• Bitter over the loss of Texas to the U.S. after its independence in 1836.
• Polk wanted California and New Mexico, offering $30 million, which Mexico refused.

The Start of the Mexican-American War

• Polk was determined to acquire the territories, viewing them as part of Manifest Destiny.
• Sent troops to occupy a disputed area on the Texas-Mexico border.
• Clashes between American troops and Mexican cavalry led Polk to declare war on May 13, 1846.

The War and Its Outcome

• Mexico was unprepared for war:
  • Internal political issues.
  • Cavalry insufficient against the U.S. military expertise.
• After two years, Mexico was defeated.
• Treaty of Guadalupe Hidalgo:
  • Mexico ceded one-third of its territory to the U.S.
  • Modern-day Utah, California, Nevada, Arizona, and Texas were included.

Impact of the Mexican-American War

• Major territorial expansion for the U.S.
• Launched the careers of notable military figures:
  • Future U.S. President Zachary Taylor.
  • Civil War figures Robert E. Lee and Ulysses S. Grant.

Conclusion

• The war significantly shaped the geographical and political landscape of the United States, fulfilling the vision of Manifest Destiny.