1. Unit 9: Westward Expansion
Lesson 5: War with Mexico

2. The U.S. officially recognized the Republic of Texas as an independent nation in 1837
What had the U.S. done in the past with many of the lands that bordered it?
Made them part of the U.S.

3. to incorporate into something larger
Congress, however, was not quick to try to make Texas a state
Any guesses why?
Texas would enter the Union as a slave state, which would throw off the balance, so many Northerners
opposed the idea of annexing Texas
(off balance)
annex:
to incorporate into something larger

4. Relations Between Texas & Mexico
Relations between Texas & Mexico had been rocky ever since Texas gained its independence
Mexico never even officially recognized Texas’ independence
For years, the 2 gov’ts fought over borders & territory

5. Tensions reached a height when Texas tried to claim land
all the way to (present-day) California

6. What was the motivation behind claiming this land?
By the mid 1840s, many Americans believed the U.S. had a “manifest destiny”
Manifest = obvious
Destiny = something that is sure to happen
Some Americans thought the U.S. was obviously meant to spread across the continent

7. So “manifest destiny” was the belief that the U. S
So “manifest destiny” was the belief that the U.S. was meant to spread all the way across the continent

9. Manifest Destiny
Those who believed in manifest destiny gave little thought to the Native Americans & Mexicans who would lose their land as the U.S. expanded

10. Annexing Texas Texans voted to seek admission to the U.S.
As soon as Texas gained its independence,
Texans voted to seek admission to the U.S.
As we mentioned, this posed a problem for the U.S.
Southerners were happy to extend their cotton-growing area,
but Northerners opposed adding another slave state to the Union

11. Tyler urged Congress to pass a joint resolution to annex TX
The outgoing President, John Tyler,
and the incoming President, James Polk,
both believed strongly in manifest destiny
In February, 1845, just before leaving office,
Tyler urged Congress to pass a joint resolution to annex TX

12. And it worked! In December, 1845, Texas became our 28th state
However, there were still some problems to be resolved
1. the boundary between TX & Mexico remained undetermined
2. the Mexican gov’t threatened to declare war

13. President Polk’s Response
He sent an agent to convince Mexico to accept the Rio Grande
as the southern border of Texas
The agent was also supposed to offer Mexico $25 mil. for (present-day) California & $5 mil. for (present-day) New Mexico

14. Mexican officials considered such a low amount of money an insult & refused to even speak with the agent

15. General Zachary Taylor
Polk, ready to get things moving, sent troops into TX under the command of
General Zachary Taylor
They set up posts just north of the Rio Grande
Although TX claimed the Rio Grande as their southern boundary, Mexico considered the land they set up posts in
to be Mexican territory

16. In April, 1846, Mexican soldiers attacked a U. S
In April, 1846, Mexican soldiers attacked a U.S. cavalry patrol, killing 11 Americans
On May 9th, Polk announced that “Mexico has shed American blood on American soil”
He then asked Congress for an official declaration of war

17. On May 13, both houses of Congress voted by a large majority to
declare war on Mexico

18. Heading to California
Soon after the war began, General Stephen Kearny led his army to Santa Fe
The Mexican governor & Mexican troops fled without firing a shot
Kearny then led about 300 soldiers to (present-day) California

19. At the time, about 500 Americans lived in California
American army Captain John C. Fremont encouraged these Americans to
revolt against the Mexicans who ruled the land they lived on

20. And They Listened
In the summer of 1846, rebels hoisted a handmade flag with a grizzly bear on it
This was their announcement that
they were creating the independent Bear Flag Republic

21. When Kearney’s troops arrived in California, they joined the rebels in fighting the Mexicans there
In January, 1847, Mexicans in California surrendered
& the U.S. took possession of the territory

22. On February 2, 1848, Mexico signed the Treaty of Guadalupe Hidalgo
By doing so, they gave up the territory that now includes CA, NV, UT, & parts of AZ, CO, WY, & NM
The U.S, agreed to pay $15 mil. in return

23. Mexico agreed to recognize Texas as part of the U.S.
They also accepted the Rio Grande as the border between TX & Mexico

24. Despite all of these gains, Americans wanted even more of Mexico’s land
Why?
Railroad owners wanted to create a southern route to the Pacific that would run
over a strip of land just south of the Gila River

25. James Gadsden, the U.S. minister to Mexico, arranged to buy this land for $10 mil.
The Gadsden Purchase completed the boundary between Mexico & the U.S.,
and enabled the U.S. to finally span the entire continent

26. How did the US get its southwestern borders?
Area 1
During America’s war with Mexico, Americans living in present-day California revolted against
the Mexicans who owned that land

27. In 1846, the rebels created the independent
Bear Flag Republic

28. In 1847, the US took possession of the California territory

29. Area 2
The treaty that ended the war with Mexico was called
the Treaty of Guadalupe Hidalgo
As part of the treaty, Mexico sold the US
much of the land between California & the Louisiana Territory

30. Mexico also recognized the
Rio Grande
as the southern border of Texas

31. Area 3
The Gadsden Purchase gave the US the southern parts of Arizona & New Mexico
It enabled the US to finally span the entire continent