Unit 9: Westward Expansion Lesson 5: War with Mexico

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.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

In 1846, the rebels created the independent Bear Flag Republic

In 1847, the US took possession of the California territory

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

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

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