5.3 Manifest Destiny and the Mexican American War

Mexican American War, California, Nueces River, Rio Grande, Zachary Taylor, Stephen Kearney, Bear Flag Republic, John C. Frémont, Winfield Scot, Treaty of Guadalupe Hidalgo, Mexican Cession, Wilmot Proviso

President Polk sent John Slidell as an envoy to Mexico (1845) to try to …

• buy Mexico’s California and New Mexico territories → Mexico refused to sell

• settle the Mexico-Texas border → Mexico insisted on the Nueces River while Polk and Slidell believed it to be the Rio Grande

immediate causes of the Mexican American War

• Polk ordered General Zachary Taylor to move toward the Rio Grande and into disputed territory

• Mexico killed 11 members of the U.S. army patrol

• Polk’s war resolution was approved by Congress despite Whig party disapproval

invasion of Mexico

• General Stephen Kearney takes New Mexico territory and South California

• John C. Frémont overthrows Mexican rule in North California and forms Bear Flag Republic

• General Zachary Taylor drives Mexican army from Texas and crosses into Northern Mexico (1847)

• General Winfield Scott invades Central Mexico and captures the capital city

consequences of the Mexican American War

Treaty of Guadalupe Hidalgo (1848) and Wilmot Proviso

Treaty of Guadalupe Hidalgo (1848)

• Mexico recognizes the Rio Grande as the southern border of Texas

• U.S. takes possession of Mexican Cession (California and New Mexico) for $15 million

  • South of the Missouri Compromise line

Wilmot Proviso (1846)

a bill proposed by David Wilmot to prohibit slavery in the Mexican Cession

• appealed to white settlers who didn’t want to compete with slave labor

• passed twice in the majority north House, defeated in majority south Senate

mountain men

considered heroic for “bringing civilization and democratic institutions to a wilderness area”