Manifest Destiny and Westward Expansion

Manifest Destiny

• Defined by John O'Sullivan (1845) as the belief that Americans had a God-given right to expand and possess the entire continent, from the Atlantic to the Pacific Ocean.
• This idea captured the existing American desire for westward expansion.

Reasons for Westward Expansion

• Access to Resources: Demand for mineral and natural resources, exemplified by the California Gold Rush of 1848.
• Economic Opportunities: Congress passed Preemption Acts during the 1830s and 1840s, making land available for cheap to anyone.
• Religious Refuge: Groups like the Mormons migrated west to escape persecution.

James K. Polk and Expansionist Policies

• Elected in 1844, Polk strongly advocated for Manifest Destiny and sought to annex Texas and Oregon.

Texas Annexation

• Background: American settlers in Texas declared independence from Mexico in 1836.
• Conflict: After initial victories by the Mexican army such as the Alamo, Texan forces led by Sam Houston captured a Mexican general and forced him to sign a treaty granting Texan independence.
• Complications: Annexation was initially complicated by the potential for war with Mexico.

Oregon Territory

• Claims: Both the British and Americans claimed the Oregon territory.
• Resolution: Polk's administration negotiated with the British, dividing the Oregon Territory at the 49th Parallel.