Overview
This lecture discusses the causes, events, and outcomes of the Mexican-American War and how it enabled the United States to achieve Manifest Destiny by acquiring land between the Atlantic and Pacific Oceans.
Causes of the Mexican-American War
- The United States annexed Texas, angering Mexico, which did not recognize Texas as independent.
- Disputed border territory between Texas and Mexico increased tensions.
- President Polk offered to buy the disputed territory, but Mexico refused.
- Polk provoked Mexico by sending troops into the disputed area, leading to a Mexican attack and a U.S. declaration of war.
Major Events and Key Figures
- The war began after Mexican forces attacked U.S. troops in the disputed area.
- California, then part of Mexico, saw U.S. settlers rebel under John C. Fremont, raising the "Grizzly Bear Flag."
- U.S. forces under Generals Zachary Taylor and Winfield Scott invaded Mexico, winning key battles at Monterey, Buena Vista, and near Mexico City.
- The war ended with the U.S. capturing the Mexican capital.
Results and Territorial Changes
- The Treaty of Guadalupe Hidalgo ended the war in 1848, ceding a large area ("Mexican Cession") to the United States.
- The Gadsden Purchase in 1853 completed the current continental U.S. boundaries.
Opposition to the War
- Some Americans, especially in the North, opposed the war, believing it was unjust and provoked by the U.S.
- Abraham Lincoln criticized the war, calling it unnecessary aggression.
Key Terms & Definitions
- Manifest Destiny — the belief that the U.S. was destined to expand across North America.
- Annexation — adding territory to a country.
- Mexican Cession — land given to the U.S. by Mexico after the war (includes present-day California, Nevada, Utah, and parts of others).
- Treaty of Guadalupe Hidalgo — the 1848 agreement ending the Mexican-American War and transferring territory to the U.S.
- Gadsden Purchase — an 1853 land purchase from Mexico, finalizing the U.S.-Mexico border.
Action Items / Next Steps
- Review the key battles and figures of the Mexican-American War.
- Study the map of territorial changes resulting from the war and subsequent purchases.
- Prepare for a discussion on the opposition to the war and its impact on U.S. politics.