Mexican American War Manifest Destiny

What is Manifest Destiny? Belief that the United States was destined to stretch across the continent from the Atlantic Ocean to the Pacific Ocean. John O’Sullivan, a newspaper editor gave the name: “Our manifest destiny [is] is to overspread and possess the whole continent…” Manifest – clear or obvious Destiny – events sure to happen

President Polk James K. Polk ran against Henry Clay in 1844. He was a Democrat and a “dark horse” and became the 11th president. Polk’s campaign was based on taking over all of the Oregon Territory: “Fifty-four forty or fight.” (He settled for half in 1846 49th parallel.)

Trouble with Mexico In 1845, Congress admitted Texas as a slave state. Mexico viewed this as an act of war because they still saw Texas as part of their country. Texas and Mexico couldn’t agree on a border between the two. Texas claimed the Rio Grande, Mexico claimed Nueces River. (100 miles of difference) Mexico said it would fight to defend its claim. Polk sent John Slidell to negotiate. $25 million for Texas, California, and New Mexico. They refused.

The War begins… Polk sent Zachary Taylor to station troops on the Rio Grande. Mexico sees this as an act of aggression, and sends an army. On April 25, 1846, a Mexican cavalry unit crossed the Rio Grande and ambushed an American patrol killing or wounding 16 American soldiers. Polk sent a war message to Congress claiming Mexico had shed American blood on American soil. Two days later the U.S. declared war. Thousands rushed to enlist in the army, mostly from western states.

Was the war justified? Americans had mixed reactions to the war. Abraham Lincoln, an Illinois representative questioned the truthfulness of the President’s message and the need for war. Northeasterners questioned the justice of men dying in such a war. Slavery became an issue as Southerners saw an opportunity to extend slavery and increase their power in Congress. Antislavery representatives introduced a bill to prohibit slavery in any lands taken from Mexico.

Capturing New Mexico and California Gen. Stephen Kearny marched his men along the Santa Fe trail to occupy New Mexico. After 650 miles, the army persuaded Mexican troops that he meant to withdraw. He took New Mexico without firing a shot. He marched on to California with a small force of soldiers, and the rest moved south towards Mexico. In California, led by John C. Fremont. Americans rebelled against Mexican rule in the Bear Flag Revolt. They arrested the Mexican commander of Northern California and raised a crude flag showing a grizzly bear. The rebels declared California independent – the Republic of California. The U.S. troops joined them in the fall. Within weeks, the Americans controlled all of California.

Invasion of Mexico The Mexican Army was larger, but the U.S. troops were led by well trained officers. General Taylor battled his way south from Texas towards Monterrey. On Feb. 22, 1847 his 4,800 troops met Santa Anna’s 15,000 Mexican soldiers at a ranch called Buena Vista. After the 1st day, Santa Ana sent Taylor a note asking him to surrender, he refused. After the end of the second day, Santa Ana reported that “both armies have been cut to pieces.” Despite their numbers, Santa Ana retreated. The second force led by General Winfield Scott landed at Veracruz on the Gulf of Mexico. He battled toward Mexico City. Mexico fell to Scott in September 1847. A Mexican officer said, “God is a Yankee.”

The Mexican Cession Treaty of Guadalupe Hidalgo – February 2, 1848 Mexico recognized Texas as a part of the U.S. Rio Grande is the border between the nations. Mexico ceded the present day area of California, Nevada, Utah, most of Arizona, and parts of New Mexico, Colorado, and Wyoming. U.S. agreed to pay Mexico $15 million. They would also pay $3.25 million of claims U.S. citizens had against Mexico. It also promised to protect the 80,000 Mexicans living in Texas and the Mexican Cession.

From Sea to Shining Sea A strip of land from southern New Mexico and Arizona was sold to the U.S. by Mexico for $10 million in 1853. (Gadsden Purchase) The US govt. wanted it for a southern transcontinental railroad. In Washington’s day, the western border of the U.S. was the Mississippi River, by 1848 it stretched from “sea to shining sea.” Later in 1848 gold was discovered in California and people rushed to the new territory.