Manifest Destiny Mexican American War PPT

Manifest Destiny (1830s-1850)

The Concept of Manifest Destiny

Manifest Destiny was the belief promoted by journalist John L. O'Sullivan in the 1840s. It held that Americans were not only destined by God but also had a moral obligation to expand their territory westward across North America.

• Expansionists aimed to acquire land toward the Pacific Ocean, as well as Mexico and Cuba, under the idea that the U.S. had a divinely ordained right to this land.

Impact of Manifest Destiny

The idea of Manifest Destiny had far-reaching effects on the political, social, and cultural landscape of the United States.

• It spurred significant westward migration, influencing U.S. foreign policy and leading to conflicts with Native American tribes and neighboring nations.

• The concept fostered a sense of American exceptionalism, often justified through notions of racial superiority and cultural destiny, which frequently led to the displacement and suffering of Indigenous peoples.

Journey of Pioneers

Westward Migration

In the 1840s, thousands of Americans embarked on westward migrations along major trails, motivated by promises of land and economic opportunity.

• The most common trails included the Oregon Trail, California Trail, Santa Fe Trail, and the Mormon Trail. Most journeys began from Independence, Missouri, and required travelers to traverse the Great Plains, with many embarking in early spring to avoid the harsh winter months.

• The journey was costly and treacherous, averaging $200-$300 per family, taking approximately 6-8 months with travelers covering only about 15 miles daily in covered wagons.

Key Trails

• Oregon Trail: A 2,000-mile journey beginning in Independence, Missouri, passing through South Pass of the Rockies, eventually leading to the Oregon Territory.

• Santa Fe Trail: Started in Independence, this trail moved southwest into what is now Texas, New Mexico, and Arizona, facilitating trade and migration.

• California Trail: Another 2,000-mile route which led from Independence to the West Coast of California. These trails significantly contributed to the U.S. government's expansionist policies and led to heightened tensions resulting in the Mexican-American War (1846-1848).

Conflicts Over Texas

American Settlement in Texas

In the 1820s, the Mexican government actively encouraged American migration to Texas to bolster its population, offering land grants. By 1835, American settlers, often slaveholders from the southern U.S., began to outnumber the native Texans, creating significant cultural and political tension.

Texas Independence

• In 1834, the Mexican government attempted to enforce a ban on slavery, which led to dissatisfaction among American settlers.

• On March 2, 1836, American settlers officially declared their independence from Mexico. The conflict culminated in the famous battle at The Alamo, where Texas forces were defeated but rallied support for their cause.

• By late 1836, Texan forces achieved victory over Mexico, leading to Texas securing its independence, although hopes for immediate annexation to the United States faced hesitation from Presidents Jackson and Van Buren due to fears of escalating sectional tensions between North and South.

Acquisition of Texas

In 1845, Texas was officially annexed by the United States, prompting Mexico to sever diplomatic relations, a move that exacerbated existing tensions.

Election of 1844

Political Dynamics

During the 1844 Presidential Convention, divisions emerged among Democrats concerning Manifest Destiny and the expansion of slavery into new territories.

• James K. Polk, a staunch supporter of westward expansion, secured the Democratic nomination by promising to fulfill the nation's desire for territorial growth.

Polk's Presidency

Serving from 1845-1849, Polk promoted Manifest Destiny through key events, including the negotiation of the Oregon Treaty and leading the nation through the Mexican-American War.

Oregon Territory

Tensions with Great Britain

Polk’s campaign famously included the slogan, “Fifty-Four Forty or Fight,” referring to the latitude at which expansionists wanted U.S. territory. This escalated tensions with Great Britain over the Oregon Territory.

• The Oregon Treaty of 1846 ultimately established U.S.-British borders along the 49th Parallel, avoiding war.

Prelude to the Mexican-American War

Boundary Disputes

Tensions escalated as disagreements over the Texas border arose; settlers claimed the Rio Grande River as the southern boundary, while Mexico asserted that the Nueces River was the true border.

• Polk pursued the acquisition of New Mexico and California but was rebuffed by the Mexican government, leading to increased military hostilities.

The Mexican-American War (1846-1848)

Outbreak of War

Polk ordered troops under General Zachary Taylor into the disputed territory. An alleged attack by Mexican forces prompted Congress to declare war on Mexico.

Opposition to the War

Prominent figures such as Abraham Lincoln, then a young congressman, openly questioned Polk’s justifications for the war, challenging the government to clarify its motives, which earned him the nickname “Spotty Lincoln.”

Outcomes of the War

• The war resulted in notable territorial gains for the U.S. including New Mexico and Southern California; California settlers declared sovereignty with the establishment of the Bear Flag Republic.

• The Treaty of Guadalupe Hidalgo (1848) formalized these acquisitions, transferring immense territories (New Mexico and California) to the U.S. for $15 million and confirming Texas's border at the Rio Grande.

Slavery Debate Post-War

Wilmot Proviso

The Wilmot Proviso, proposed by David Wilmot, aimed to ban slavery in any territory acquired from Mexico. It was passed in the House of Representatives but failed in the Senate, intensifying sectional discord.

Sectional Tensions

Newly acquired territories ignited fierce debates about the expansion of slavery, exacerbating the divide between Northern and Southern states and foreshadowing the Civil War.

The California Gold Rush

Discovery and Impact

The discovery of gold in California in January 1848 accelerated westward migration as thousands flocked to the region in search of fortune. These individuals, known as the Forty-Niners, significantly impacted both the economy and demographics of the area.

• An influx of settlers seeking wealth led to a critical disruption in the balance between free and slave states when California sought admission as a free state in 1849.

Political Reactions

In response to California's statehood, southern politicians proposed extending the Missouri Compromise line all the way to the Pacific; however, then-President Zachary Taylor advocated for immediate statehood for both California and New Mexico as free states.

Compromise of 1850

Legislative Outcomes

The Compromise of 1850 consisted of several crucial provisions: California was admitted as a free state; popular sovereignty was implemented in New Mexico and Arizona; the slave trade was abolished in Washington D.C., and a stricter Fugitive Slave Law was enacted.

Presidential Impact

President Zachary Taylor initially opposed the Compromise but died in the summer of 1850, allowing it to pass under his successor Millard Fillmore's administration.

Significance of Manifest Destiny and the Mexican-American War

The Mexican-American War not only reinforced ideas of Manifest Destiny but also rekindled the national debate over slavery, leading to increased sectional strife and setting the stage for the Civil War (1861-1865).

• The failure of political compromises deepened mistrust and division between the North and South, signaling the impending conflict.