Expanding West The Mexican-American War Chapter 11, Section 3 Pages 354 - 363

Building Background Mexican independence set the stage for conflict and change in the West and Southwest. At the same time, American settlers continued to move westward settling in the Mexican territories of Texas and California. American ambitions led to clashes with Mexico and the people who already lived in Mexico’s territories.

Manifest Destiny Some people believed it was America’s manifest destiny, or obvious fate, to settle land all the way to the Pacific Ocean in order to spread the concept of democracy. In the 1840s and 1850s, manifest destiny was tid\ed up with the slavery issue. If American expanded, would slavery be allowed in the new territores?

Disagreement Several presidents became involved with the slavery issue. Among them was President John Tyler. Tyler was a pro-slavery Whig who wanted to increase the power of the southern slave states by annexing Texas. His fellow Whigs disagreed. Tyler was not selected by the Whigs to be their candidate in the 1844 election.

1844 Election The Whigs chose Senator Henry Clay of Kentucky as its presidential candidate. The Democrats select former Tennessee governor James K. Polk. Both candidates strongly favored acquiring Texas and Oregon. Southerners feared the loss of Texas, a possible new slave state. Others worried that Texas might become an ally of Britain. These concerns helped Polk narrowly defeat Clay.

Acquiring New Territory President Polk quickly set out to fulfill his campaign promise to annex Oregon and Texas. By the 1820s, Russia and Spain had given up their claims to the Oregon Country. Britain and the United States agreed to occupy the territory together. As more Americans started settling in Oregon, the demand to become part of the United States increased.

“Fifty-four Forty or Fight!” Britain and the United States disagreed over how to draw the border between the U.S. and Canada. American expansionists cried, “Fifty-four forty or fight!” This slogan referred to the 54°40’ north latitude, the line to which Americans wanted their northern territory to extend. In 1846 Great Britain and the United States signed a treaty that gave the U.S. all of the Oregon land south of the forty-ninth parallel.

Texas By March 1845, Congress had approved annexation of Texas and needed only the support of the Republic of Texas. Texas politicians hoped that joining the U.S. would help solve financial and military problems. The Texas Congress approved annexation in June 1845. Texas became part of the U.S. in December. Mexico considered Texas to be a stolen province.

California Under Mexico During early Spanish rule, the mission system had dominated much of the present-day Southwest. Missions were the focus of everyday life. Missions carried out huge farming and ranching operations using the labor of Native Americans. Missions often sold their goods to local pueblos, or town, that were near the missions and presidios.

California Under Mexico During early Spanish rule, the mission system had dominated much of the present-day Southwest. Missions were the focus of everyday life. Missions carried out huge farming and ranching operations using the labor of Native Americans. Missions often sold their goods to local pueblos, or town, that were near the missions and presidios.

Californios and Anglos By the 1820s California only had around 3,200 colonists. These early settlers, called Californios, felt little connection to the Mexican government which was hundreds of miles away in Mexico. In addition to traders and travelers, a small number of settlers arrived from the United States. They were called Anglos by the Californios. Anglo call for independence created tension between Mexico and the United States.

Mexican-American War Conflict Breaks Out Mexico had long insisted that its northern border lay along the Nueces River. The United States said the border was farther south, along the Rio Grande. In June 1845 President Polk ordered General Zachary Taylor to lead an army into the disputed region. Polk also sent diplomat John Slidell to Mexico City to try to settle the border dispute.

Armed Encounter In March 1846, General Taylor led his forces to the Rio Grande River. He camped across from Mexican forces stationed near the town of Matamoros. In April, the Mexican commander told Taylor to withdraw from Mexican territory. Taylor refused to withdraw and the two sides exchanged gun fire. Several U.S. soldiers were killed. President Polk went to Congress and claimed that Mexican forces invaded the U.S. and spilled American blood on American soil.

Armed Encounter In March 1846, General Taylor led his forces to the Rio Grande River. He camped across from Mexican forces stationed near the town of Matamoros. In April, the Mexican commander told Taylor to withdraw from Mexican territory. Taylor refused to withdraw and the two sides exchanged gun fire. Several U.S. soldiers were killed. President Polk went to Congress and claimed that Mexican forces invaded the U.S. and spilled American blood on American soil.

War Begins At the beginning of the war with Mexico, the U.S. Army had better weapons and equipment. Yet it was greatly outnumbered and poorly prepared. The government put out a call for 50,000 volunteers and about 200,000 responded. Many members of the Whig Party thought the war was unjustified and avoidable. Northern abolitionists also opposed the conflict. They feared that slavery would spread into southwestern lands.

Early Battles While the Americans debated the war, fighting began. General Taylor’s men won battles south of the Nueces River and took control of the town of Matamoros. Polk ordered General Stephen Kearny to attack New Mexico and on August 18, 1846 Kearny took control of Santa without a fight. After claiming the entire province of New Mexico for the U.S., Kearny’s forces marched west to California.

The Bear Flag Revolt In 1846, only about 500 Americans lived in the huge province of California, in contrast to about 12,000 Californios. A small group of Americans seized the town of Sonoma on June 14, 1846. Fighting began between the two sides when the Americans took some horse that were intended to be used by the Mexican militia. In what became known as the Bear Flag Revolt, the Americans declared California to be an independent nation.

John C. Frémont U.S. Captain John C. Frémont (on a mapping expedition in the Nevada territory) quickly went to Sonoma and joined the American revolt. Frémont stated that his goal was to help in California becoming independent and not to annex California for the U.S. The Bear Flag Revolt was quickly put down, however U.S. naval forces came ashore in California and raised the flag of the United States. U.S. forces quickly took control of San Diego, Los Angeles, and San Francisco.

War’s End General Taylor drove his forces deep into Mexico and encountered the army led by Santa Anna. The two armies clashed at Buena Vista in February 1847, resulting in the retreat of the Mexican forces after an intense battle. Taylor became a war hero back in the U.S., but this threatened President Polk. Polk replaced Taylor after he failed to make progress with General Winfield Scott. Scott quickly captured the port city of Veracruz in March.

War’s End Scott moved on to his final objective – Mexico City. After a truce failed, Scott ordered a massive attack on Mexico City in August 1847. Mexico City finally fell to the U.S. forces on September 14, 1847. General Santa Anna fled the country.

Mexican Cession In February 1848, the U.S. and Mexico signed the Treaty of Guadalupe Hidalgo. This treaty gave most of its northern territory to the U.S. Known as the Mexican Cession, this land included the present-day states of California, Nevada, and Utah. It also included most of Arizona and New Mexico and parts of Colorado and Wyoming. The Mexican Session totaled more than 500,000 square miles and increased the size of the U.S. by almost 25%.

The Gadsden Purchase In 1853 the United States paid Mexico an additional $10 million for a strip of land along the southern edge of present-day Arizona and New Mexico, called the Gadsden Purchase. With the Gadsden Purchase, the adjoining 48 states of the mainland reached its present size.