Mexican-American War

Texas declared independence from Mexico in 1836, leading to tensions.
Texas sought annexation by the U.S., opposed by Mexico.
Presidents Jackson, Van Buren, Harrison, and Tyler initially resisted annexation.
James K. Polk, elected in 1845, campaigned on annexing Texas.
John Tyler initiated the annexation before leaving office, influenced by Polk's election.
Polk sent John Slidell to negotiate with Mexico for land (New Mexico, California) and border settlement, but was rejected.
Border dispute: U.S. claimed the Rio Grande, while Mexico claimed the Nueces River.
Polk sent General Zachary Taylor to the Rio Grande, leading to a confrontation and American casualties.
Congress declared war on Mexico on May 13, 1846.

U.S. gained significant land through the Treaty of Guadalupe Hidalgo in 1848.
- Rio Grande established as the southern border of Texas.
- Mexican Cession: Mexico ceded California and New Mexico to the U.S. for $15$ million.
- Mexico lost over half its territory to the U.S., including the Gadsden Purchase.
Wilmot Proviso (1846): Proposed that slavery be prohibited in any territory acquired from Mexico, but was voted down.
- Highlighted growing tensions over slavery and the ideal of free soil.
- Considered by some historians as a precursor to the Civil War.
Treaty of Guadalupe Hidalgo granted citizenship to Mexicans living in the ceded territories, but not to Indians. Both groups faced civil rights assaults, including voter discrimination and educational segregation.