AP U.S. History - Unit 5: Manifest Destiny and Westward Expansion (1844-1877)

Key Concepts

• Manifest Destiny: Coined by John O'Sullivan in 1845, it is the belief that Americans had a God-given right to expand their nation across the continent from the Atlantic to the Pacific Ocean.
• Influence on Policy: This belief influenced American expansion policies, including pursuing territories like Texas and Oregon.

Motivations for Westward Expansion

1. Access to Resources:

   • Discovery of gold in California (1848) led to the California Gold Rush.
   • Other mineral discoveries in Colorado, the Dakotas, and Nevada.

2. Economic Opportunities:

   • Preemption acts in the 1830s and 1840s made land available for cheap, encouraging homesteading.
   • Primarily the middle class moved west due to the costs involved.

3. Religious Refuge:

   • Mormons moved to the Utah territory seeking refuge from persecution.
   • Continued migration of Mormons for 20 years, approximately 70,000 people.

Impact on Politics and Territories

• Election of James K. Polk (1844):
  • Polk was a strong supporter of Manifest Destiny.
  • Sought to annex Texas and Oregon, and aimed for expansion into California.

Texas Annexation

• American Settlement:

  • Since the 1820s, Americans settled in Mexican-owned Texas.
  • By 1830, Americans outnumbered Mexicans 3:1, mainly Southern Protestants and slave owners.

• Mexican Requirements (1829):

  • Convert to Roman Catholicism.
  • Abolish slavery.
  • Americans largely ignored these requirements.

• Conflict and Independence:

  • Mexico closed the border to immigration.
  • 1834: Mexican government change led to stricter enforcement, prompting Texan revolt.
  • Texas declared independence in 1836 under Sam Houston.
  • Treaty signed under duress at the Battle of San Jacinto, unrecognized by the Mexican government.

• American Response:

  • Texas sought U.S. statehood.
  • Presidents Jackson and Van Buren avoided annexation to prevent war with Mexico.
  • John Tyler attempted annexation, denied by Senate.

Oregon Territory

• British vs. American Claims:

  • British had longstanding fur trade, Americans wanted the land and were settling in larger numbers.

• Resolution Under Polk:

  • Polk's election was seen as a mandate for expansion.
  • Agreement with Britain divided Oregon at the 49th parallel.

Consequences

• Annexation of Texas:
  • Led to tensions with Mexico, setting the stage for war.

Conclusion

• This lecture covers the motivations and political maneuvers surrounding westward expansion in the mid-19th century. The actions taken under the belief of Manifest Destiny significantly shaped the United States' territorial boundaries and its political landscape.

Additional Resources

• Consider reviewing supplementary material for a deeper understanding of how these events led to the Mexican-American War, which will be covered in the next lecture.