Unit 5.2/3

Definition: The belief that Americans had a God-given right to expand their nation from the Atlantic to the Pacific Ocean.
Origin: The term was coined in 1845 by newspaper editor John O'Sullivan.
**Reasons for Westward Expansion: ** * Access to mineral and natural resources (e.g., California Gold Rush in 1848).
- Economic and homesteading opportunities (Preemption Acts made land available cheaply).
- Religious refuge (e.g., Mormons fleeing persecution to the Utah territory).
Political Influence: James K. Polk's election in 1844 reflected the support for westward expansion.

Texas:
- Americans settled in Texas (belonging to Mexico) in the 1820s.
- Tensions arose due to disagreements over religion and slavery.
- Texas declared independence in 1836 after revolt led by Sam Houston.
- Annexation to the U.S. was initially declined due to the potential for war with Mexico.
Oregon:
- Both British and Americans claimed the territory.
- Polk advocated for annexation, resulting in a treaty dividing Oregon at the 49th Parallel.

Texas Annexation: Mexico opposed the annexation of Texas by the U.S.
Border Dispute: Disagreement over the southern border of Texas (Nueces River vs. Rio Grande).
Polk's Actions: Polk sent troops led by General Zachary Taylor to the Rio Grande, leading to conflict.

Treaty of Guadalupe Hidalgo (1848):
- Established the Rio Grande as the southern border of Texas.
- Mexico ceded California and New Mexico to the U.S. for $15 million$ (Mexican Cession).
Wilmot Proviso: Proposed that slavery be prohibited in any lands acquired from Mexico, but was voted down.
Impact on Residents:
- Mexicans living in the ceded territories were granted U.S. citizenship.
- Indians were not offered citizenship and faced discrimination.