Overview
This lecture covers the causes, motivations, and consequences of American territorial expansion in the 19th century, setting the stage for events leading to the Civil War.
Causes and Ideology of American Expansion
- The concept of Manifest Destiny justified the U.S. expansion across North America.
- Americans believed westward movement was both inevitable and a right.
- Economic opportunities, access to land, and national security motivated expansion.
Key Events in American Expansion
- The Louisiana Purchase in 1803 doubled the size of the U.S. territory.
- The annexation of Texas in 1845 contributed to tensions with Mexico.
- The Mexican-American War (1846-1848) resulted in the U.S. acquiring modern-day California, Arizona, and New Mexico.
- The Oregon Trail was a major route for settlers moving west.
Consequences of Expansion
- Expansion intensified debate over the extension of slavery into new territories.
- Native American populations were displaced and suffered as settlers moved west.
- Sectional tensions between the North and South increased due to disagreements over slavery and state rights.
Prelude to the Civil War
- Disputes over whether new states would be slave or free led to increased conflict.
- The Compromise of 1850 and the Kansas-Nebraska Act attempted to address the slavery issue but increased sectionalism.
- Political compromise became more difficult as expansion continued.
Key Terms & Definitions
- Manifest Destiny — Belief that Americans were destined to expand across the continent.
- Louisiana Purchase — 1803 land deal doubling the size of the U.S.
- Mexican-American War — 1846-1848 conflict resulting in U.S. gaining southwestern territories.
- Sectionalism — Loyalty to the interests of one's region rather than the country as a whole.
- Compromise of 1850 — Law intended to ease tensions over slavery in new territories.
Action Items / Next Steps
- Review textbook chapter on westward expansion and the causes of the Civil War.
- Prepare to discuss the effects of the Mexican-American War in the next class.