Mexican-American War1846-1848

Adams-Onis Treaty1819

• Spain & U.S. sign treaty

• Gives Florida to U.S.

• Sets U.S./Mexico border

Before the War 1819 – The U.S. and Spain determine Mexico-U.S.

boundary

1821 – Mexican Independence

1823 – Mexico offered cheap land to Americans who wanted to settle in Texas

Annexation of Texas Texas wins independence from Mexico, Texans voted to join the U.S.

(1844)

Americans divided: Another potential slave state Could lead to war with Mexico

Mexican leader Santa Anna warned that Texas annexation would be “equivalent to a declaration of war against the Mexican Republic.”

Polk Wins, Texas Joins

In 1844, Polk (strong supporter of expansion) won the presidency

In 1845, Congress approved annexation

Steps to War

July of 1845 – President Polk

orders General Zachary Taylor to

Texas

Why did the Mexican-American War begin?

Quick Source

Read the quote:

Who started the war?

Should we trust this source?

Document A Source:

What’s the most important thing about the source? How might it influence what this source says?

Finish reading Document A

Answer questions 1-3 with your partner

Document B

Read Document B

Answer questions 4-9

What are your initial conclusions?

What are the differences between the accounts?

Which do you believe, and why?

Mexican-American War Begins

In 1846, American troops marched toward the Rio Grande

Mexican army kills several of the people they see as invaders

In 1846, Polk declares war on Mexico

Mexican-American War Key Events

June of 1846 - California settlers write a Constitution and declare themselves a republic Quickly declare themselves part of the U.S.

1847 – American troops occupy Mexico City

Treaty of Guadalupe Hidalgo, 1848

United States got 500,000+ square miles of valuable territory

U.S. also emerged as a world power

America expanded to the Pacific

Final Qs

1. Why did the Mexican-American War begin?

2. How is Manifest Destiny related to the Mexican-American War?

3. One paragraph answer:

Overall, did Manifest Destiny primarily have a positive impact or a negative impact? Why? Use specific historical evidence to support your point.