THE MEXICAN AMERICAN WAR

THE MEXICAN AMERICAN WAR

The slogan “Manifest Destiny” was coined in 1845 by

John L. O’Sullivan and referred to the territorial growth the United States

experienced in the 1800s. “Manifest Destiny” expressed the conviction that the

country’s superior institutions and culture gave America a God-given right, even an

obligation, to spread their civilization across the entire continent.

1

While James K. Polk campaigned

for the presidency in 1844, he

promised the American people

that if he was elected he would

expand the country. He won the

election and became the 11th

president of the United States.

2President James K. Polk

MEXICO in 1821

In 1845 Congress admitted Texas

as a state. This made the Mexican

government very angry. They still

believed that Texas was a part of

Mexico.

3

In September 1845 President Polk

sent John Slidell to Mexico City to

negotiate the disputed Texas

border and purchase New Mexico,

California, and Texas for $25

million. Mexico disagreed with

the border the U.S. claimed and

turned down the money offer.

4

John Slidell

In March 1846 President Polk sent General

Zachary Taylor and his troops into the

disputed territory (land that both the U.S.

and Mexico claimed as its own) between

the Rio Grande and Nueces Rivers.

5

General Zachary Taylor

On April 25, 1846 Mexican troops cross the Rio Grande River and opened fire on U.S.

troops at Fort Texas. On May 13, 1846 Congress officially declared war on Mexico.6

At the start of the war only about

75,000 Mexican citizens lived north of

the Rio Grande. As a result, U.S. forces

led by Col. Stephen W. Kearny and

Commodore Robert F. Stockton were

able to conquer those lands with

minimal resistance.

7

Colonel Stephen Kearney

With the losses adding up, Mexico turned to

old standby General Antonio López de Santa

Anna, the charismatic strongman who had

been living in exile in Cuba. Santa Anna

convinced Polk that, if allowed to return to

Mexico, he would end the war on terms

favorable to the United States. But when he

arrived, he immediately double-crossed Polk

by taking control of the Mexican army and

leading it into battle. At the Battle of Buena

Vista in February 1847, Santa Anna suffered

heavy casualties and was forced to withdraw.

Despite the loss, he assumed the Mexican

presidency the following month.8

General Antonio Lopez de Santa Anna

Meanwhile, U.S. troops led by Gen. Winfield Scott landed in Veracruz and took over

the city. They then began marching toward Mexico City. The Mexicans resisted at

Cerro Gordo and elsewhere, but were defeated each time. In September 1847,

General Winfield Scott successfully laid siege to Mexico City’s Chapultepec Castle.

During that clash, six military school cadets committed suicide rather than surrender.

9General Winfield Scott

On February 2, 1848, Mexican and U.S. officials signed the Treaty of Guadalupe

Hidalgo officially ending the War. This treaty gave the United States California,

Nevada, Utah, most of Arizona, and parts of New Mexico, Colorado, and Wyoming.

10