Fruits of Manifest Destiny

Continental Expansion

In the 1840s, slavery became a central issue due to territorial expansion, not abolitionist demands.
By 1840, white control extended over almost all land east of the Mississippi River after Indian removal.
Economic depression in 1837 drove settlers westward, especially to Oregon's Willamette Valley.
Between 1840 and 1845, approximately 5,000 people traveled by wagon train from the Missouri River to Oregon.
By 1860, nearly 300,000 people had settled in Oregon and California, facing disease, hunger, the Rocky Mountains, and conflicts with Native Americans.
During the 1840s, the U.S. and Great Britain shared control of Oregon, while Utah was part of Mexico.
Manifest Destiny: The belief that the United States was destined to expand across the continent to the Pacific Ocean.

The Texas Revolt

After Mexico gained independence from Spain in 1821, it was nearly as large as the United States, with a population of 6.5 million.
Texas attracted American settlers after Mexico gained independence.
Tejanos: People of Spanish descent in Texas, numbering about 2,000.
Moses Austin received a land grant from Mexico to bring American settlers to Texas.
Stephen Austin carried out his father's plan, selling land to American settlers for twelve cents an acre.
By 1830, Americans in Texas numbered about 7,000, outnumbering the Tejanos.
In 1830, Mexico annulled existing land grants and banned further American immigration due to concerns about losing control.
Under Stephen Austin's leadership, American settlers demanded more self-governance, joined by some Tejanos.
The issue of slavery increased tensions despite Mexico abolishing it, as American settlers brought enslaved people into Texas.
In 1835, General Antonio López de Santa Anna, Mexico's ruler, sent an army to enforce central authority, leading to accusations that he aimed to free slaves and enslave the settlers.
The actions of Santa Anna led to a chaotic revolt in Texas, resulting in the declaration of Texan independence.
On March 6, 1836, Santa Anna's army attacked the Alamo in San Antonio, killing all 187 American and Tejano defenders.
"Remember the Alamo" became a rallying cry for the Texans.
In April, Sam Houston led Texan forces to victory at the Battle of San Jacinto, capturing Santa Anna.
Santa Anna was forced to recognize Texas's independence, and Houston was later elected the first president of the Republic of Texas.
In 1837, the Texas Congress requested to join the United States, but Presidents Andrew Jackson and Martin Van Buren delayed due to fears of political conflicts regarding slavery.
By 1845, the population of Texas had grown to nearly 150,000, including many slave owners seeking fertile cotton land.

The Election of 1844

President John Tyler brought the annexation of Texas back into the political spotlight to save his administration and gain southern support for reelection in 1844.
A letter by John C. Calhoun, Tyler's secretary of state, was leaked, tying the annexation of Texas to strengthening slavery.
Some southern leaders hoped Texas could be divided into multiple states, increasing the South's power in Congress.
Henry Clay and Martin Van Buren opposed the immediate annexation of Texas, fearing war with Mexico.
Clay secured the Whig nomination, but Van Buren lost the Democratic nomination due to his stance on annexation.
Southern Democrats withdrew their support from Van Buren, and the party turned to James K. Polk.
Polk's key advantages were his support for annexation and his ties to Andrew Jackson.
Polk was a slaveholder with large cotton plantations and the conditions for enslaved people on Polk's plantations were so harsh that only half the childrenlived to age 15, and many adults tried to escape.
Democrats included "reannexing" Texas and "reoccupying" Oregon in their platform to unify the party.
The slogan "Fifty-four forty or fight" rallied support for demanding U.S. control of Oregon up to its northern border at latitude 54°40'.
Many northern Democrats felt betrayed by the South, creating long-lasting political divisions.
In the 1844 election, Polk narrowly defeated Clay. James G. Birney, the Liberty Party candidate, took votes in New York, which would have allowed Clay to win.
In March 1845, Congress voted to make Texas part of the United States.

The Road to War

James K. Polk planned to lower tariffs, restore the independent Treasury system, resolve the Oregon ownership dispute, and bring California into the Union.
Congress quickly passed measures to lower tariffs and reestablish the Treasury system.
An agreement with Great Britain in 1846 divided Oregon at the forty-ninth parallel, upsetting some northerners.
Polk secured key areas, including the Willamette Valley and Puget Sound's strategic harbor.
Polk sent a representative to Mexico to buy California, but Mexico refused to negotiate.
By the spring of 1846, Polk prepared for military action.
In April, American troops led by General Zachary Taylor moved into the disputed territory between the Nueces River and the Rio Grande.
Polk declared that Mexico had "shed blood upon American soil" and asked Congress to declare war.

The War and Its Critics

The Mexican War was the first American conflict fought mainly on foreign soil and the first where American troops occupied a foreign capital.
Most Americans supported the war because of manifest destiny.
Many believed Americans carried "the ark of Liberties" for all humanity and that "national selfishness is unbounded philanthropy… to the world."
Some Northerners opposed the war, suspecting its purpose was to expand slavery.
Ulysses S. Grant called it "one of the most unjust ever waged by a stronger nation against a weaker nation."
Abraham Lincoln questioned Polk's claim that Mexico started the conflict.
In 1847, Lincoln introduced a resolution asking Polk to specify the exact "spot" where blood was shed.
Lincoln warned against giving the president unchecked power to invade other countries.
The United States and Mexico signed the Treaty of Guadalupe Hidalgo in February 1848.
The treaty confirmed the annexation of Texas and ceded California, New Mexico, Arizona, Nevada, and Utah to the United States.
The U.S. paid Mexico 15 million in return.
This land acquisition, called the Mexican Cession, established most of the modern U.S. borders, except for the Gadsden Purchase (1853) and Alaska (1867).
The Mexican War is largely overlooked in American historical memory but is remembered in Mexico as "the dismemberment."
Mexicans view the war as unjust, as it was unprecedented for a country to start a war because another refused to sell its land.

Race and Manifest Destiny

After the Mexican War, the United States gained half a million square miles of territory.
The new border split a region that had been united for centuries.
Around 75,000 to 100,000 Spanish-speaking Mexicans and over 150,000 Native Americans lived in the newly acquired land.
The Treaty of Guadalupe Hidalgo promised Mexican male citizens "the free enjoyment of their liberty and property" and "all the rights" of U.S. citizens.
The treaty only referred to Native Americans as "savage tribes."
Manifest destiny intensified ideas about racial superiority.
By the 1840s, territorial expansion was seen as proof of the superiority of the "Anglo-Saxon race."
"Race" was a flexible concept that included skin color, culture, national origin, class, and religion.
Newspapers, magazines, and scholars promoted the idea that American freedom was linked to the liberty-loving nature of Anglo-Saxon Protestants.
Some expansionists wanted the U.S. to annex all of Mexico, but these efforts failed due to fears that the country could not absorb its large non-white Catholic population.

Redefining Race

American race relations brought harm to people in the territories gained from Mexico.
Texas constitution protected slavery and denied civil rights to Native Americans and African Americans after gaining independence.
Only white people were allowed to buy land, and free Black people were banned from entering the state.
Racial classifications varied based on local conditions.
In Texas, "Spanish" Mexicans with higher social status were classified as white.
Because white settlers were slow to move into New Mexico, Congress refused to make it a state until 1912.

Gold-Rush California

A frenzy for gold swept across the globe, attracting migrants from around the world to California.
California's non-Native population swelled to 200,000 by 1852 and over 360,000 by 1860.
Experienced miners came from Mexico and South America, while many Americans from the eastern United States joined the rush.
Immigrants poured in from Ireland, Germany, Italy, and Australia.
Nearly 25,000 Chinese men arrived between 1849 and 1852, working under long-term labor contracts.
San Francisco grew from a population of 1,000 in 1848 to 30,000 by 1850, becoming one of the most racially and ethnically diverse cities in the world.
The gold rush drew mostly young men.
Women played important roles in mining towns, running businesses and working in various occupations.
In 1860, the male population was almost three times larger than the female population in California.