The Mexican-American War | AP US History Class Notes

Overview

• Conflict between the United States and Mexico (1846-1848)
• Triggered by U.S. annexation of Texas and border disputes

Context to the War

• Texas War of Independence (1835-1836)
  • Initiated by American settlers establishing the Republic of Texas
  • Ended with Texan victory at the Battle of San Jacinto
  • Iconic Battles: The Alamo, Goliad
  • Resulted in the Republic of Texas, annexed by U.S. in 1845

Causes of the War

• Border Dispute: U.S. claimed Rio Grande, Mexico claimed Nueces River
• Annexation of Texas: Mexico never recognized Texan independence
• U.S. Expansionist Policies: Driven by Manifest Destiny and economic interests
• Military Provocations: U.S. troops led by General Zachary Taylor stationed along Rio Grande, perceived as provocation by Mexico

The Treaty of Guadalupe Hidalgo

• Signed February 2, 1848
• Mexico ceded large territories to U.S. (California, Nevada, Utah, Arizona, New Mexico, parts of Colorado and Wyoming)
• U.S. paid Mexico $15 million and assumed claims of American citizens
• Provisions for Mexican citizens in ceded lands were not fully respected

Effects of the War

• Territorial Changes: Significant U.S. land acquisitions known as Mexican Cession
• Economic and Political Impacts: U.S. economic growth; Mexico faced debt and political instability
• Slavery and Race Relations: Debate over slavery in new territories intensified
• Impact on Native Americans: Displacement and cultural disruptions
• U.S.-Mexico Relations: Long-term bitterness and mistrust

The Wilmot Proviso

• Proposed ban on slavery in territories acquired from Mexico
• Failed in the Senate, highlighted North-South tensions
• First congressional attempt to limit slavery expansion

Key Terms and Figures

• Manifest Destiny: Ideological belief in U.S. territorial expansion
• Sam Houston: Led Texas forces during the Texas Revolution
• General Santa Anna: Mexican general defeated at Texas battles
• Battle of San Jacinto: Decisive victory for Texan independence
• Rio Grande vs. Nueces River: Central to border disputes
• President James K. Polk: Advocated for U.S. expansion
• General Zachary Taylor: U.S. military leader during the war
• Mexican Cession: Territory ceded by Mexico to U.S.
• Wilmot Proviso: Legislative proposal to ban slavery in new territories

This guide covers the causes, major events, and effects of the Mexican-American War, providing context to its historical significance and impact on subsequent U.S. policy and conflicts.