9.2 The Mexican-American War and the Treaty of Guadalupe Hidalgo

The Mexican-American War, sparked by the U.S. annexation of Texas and border disputes, reshaped North America. From 1846 to 1848, U.S. forces fought their way to Mexico City, leading to a decisive American victory and major territorial gains.

The Treaty of Guadalupe Hidalgo ended the war, ceding vast Mexican lands to the U.S. This acquisition reignited slavery debates, impacted Native American tribes, and set the stage for future conflicts, profoundly altering the continent's political landscape.

Mexican-American War Origins

Texas Revolution and Annexation

• The Texas Revolution in 1836 resulted in the establishment of the independent Republic of Texas
  • Texas gained independence from Mexico after the Battle of San Jacinto
• The United States annexed Texas in 1845, despite Mexico's claims to the territory
  • U.S. President John Tyler signed a bill to annex Texas just before leaving office
  • Mexico viewed this as an act of aggression and broke diplomatic ties with the U.S.

Border Dispute and Thornton Affair

• The U.S. and Mexico disagreed on the southern border of Texas
  • The U.S. claimed the Rio Grande as the boundary
  • Mexico insisted on the Nueces River, located further north
• In 1846, U.S. President James K. Polk sent troops under General Zachary Taylor to the disputed area
• The Thornton Affair, a skirmish between U.S. and Mexican forces, occurred in the disputed territory
  • Mexican cavalry attacked a U.S. patrol led by Captain Seth Thornton
  • Polk used this incident as a pretext for declaring war on Mexico

U.S. Offensive and Key Battles

• The U.S. launched a three-pronged offensive against Mexico
  • General Zachary Taylor advanced from the north into northern Mexico
  • General Stephen W. Kearny captured New Mexico and California
  • General Winfield Scott conducted an amphibious landing at Veracruz and marched towards Mexico City
• Key battles included:
  • Battle of Palo Alto (May 8, 1846): U.S. victory under General Taylor
  • Battle of Monterrey (September 21-24, 1846): U.S. forces captured the city of Monterrey
  • Battle of Buena Vista (February 22-23, 1847): U.S. victory despite being outnumbered by Mexican forces
  • Battle of Cerro Gordo (April 18, 1847): U.S. victory under General Scott, opening the way to Mexico City
• The U.S. forces eventually captured Mexico City in September 1847, effectively ending major combat operations

Treaty of Guadalupe Hidalgo

Provisions and Territorial Changes

• The Treaty of Guadalupe Hidalgo, signed on February 2, 1848, ended the Mexican-American War
  • Established new borders between the United States and Mexico
• Mexico ceded a vast territory to the United States, known as the Mexican Cession
  • Included present-day California, Nevada, Utah, and parts of Arizona, New Mexico, Colorado, and Wyoming
  • In exchange, the U.S. paid Mexico $15 million and agreed to assume $3.25 million in claims against Mexico by U.S. citizens
• The treaty guaranteed the property rights of Mexicans living in the ceded territories
  • However, many faced discrimination and loss of land in the following years due to legal manipulation and language barriers

Consequences for the United States and Mexico

• The acquisition of new territories reignited debates over the expansion of slavery in the United States
  • The Wilmot Proviso, which sought to ban slavery in the new territories, failed to pass Congress
  • The Compromise of 1850 temporarily defused tensions by admitting California as a free state and allowing popular sovereignty in other territories
• The Mexican Cession contributed to growing sectional tensions that would eventually lead to the American Civil War
• For Mexico, the loss of nearly half its territory was a devastating blow
  • Affected national pride and economic potential
  • Led to political instability and resentment towards the United States
• The U.S. agreed to prevent Native American raids into Mexico from the ceded territories, but this provision was largely ignored

War's Impact on Native Americans

Tribes Under U.S. Jurisdiction

• Native American tribes in the ceded territories found themselves under U.S. jurisdiction after the war
  • Affected tribes included the Navajo, Apache, Comanche, and Pueblo
• The U.S. government's policies towards these tribes were often characterized by:
  • Forced relocation to reservations
  • Attempts at assimilation through education and cultural suppression
  • Broken treaties and encroachment on tribal lands

Conflicts and Wars

• The influx of American settlers and the discovery of gold in California led to increased conflicts with Native American tribes
  • Mariposa War (1850-1851): Conflict between settlers and Native Americans in the Sierra Nevada foothills
  • Mendocino War (1859): Clashes between settlers and the Yuki tribe in Northern California
• The U.S. Army established military posts throughout the region to protect settlers and control Native American populations
  • Led to further conflicts and displacement of tribes
• The Long Walk of the Navajo (1864): Forced relocation of the Navajo people from their homeland to the Bosque Redondo reservation
• The Apache Wars (1849-1886): Series of conflicts between the U.S. military and various Apache tribes in the Southwest

Loss of Land and Cultural Impact

• Native American tribes faced loss of land and forced assimilation through policies like the Indian Appropriations Act (1851)
  • This act allocated funds for the relocation of Native Americans to reservations and the establishment of boarding schools
• Traditional ways of life were disrupted and destroyed as a result of American westward expansion facilitated by the Mexican Cession
  • Loss of hunting grounds, sacred sites, and cultural practices
  • Forced adoption of European-American customs, language, and religion in boarding schools