UNIT 5, CH 13

The Mexican War was caused by U.S. expansionism—especially Manifest Destiny—and President Polk’s desire to acquire California and the Southwest. Once the U.S. gained vast new lands, the central question became whether slavery would expand into them. Proposals like the Wilmot Proviso, the rise of the Free-Soil movement, and conflicts over popular sovereignty all intensified political division. Each attempt at compromise—from the Compromise of 1850 to the Kansas-Nebraska Act—only deepened mistrust and led to outbreaks of violence such as “Bleeding Kansas.” Court decisions like Dred Scott and moral activism such as Uncle Tom’s Cabin further polarized North and South. Ultimately, territorial expansion after the Mexican War ignited a fierce sectional crisis that pushed the nation toward civil war.

Manifest Destiny

Belief that the United States was meant to expand across North America

Californios

Mexican residents of California before and after U.S. annexation

James K. Polk

U.S. president who strongly promoted territorial expansion and led the nation into the Mexican War

“Fifty-four forty or fight!”

Slogan demanding full U.S. control of the Oregon Territory up to latitude 54°40′

Conscience Whigs

Northern Whigs who opposed slavery on moral grounds

Wilmot Proviso

Proposed law to ban slavery in any land taken from Mexico

Free-soil movement

Political effort to keep western territories free of slavery

Frederick Douglass

Leading Black abolitionist, writer, and speaker against slavery

Lewis Cass

Senator who proposed popular sovereignty as a solution to the slavery issue

Squatter sovereignty (popular sovereignty)

Idea that settlers in a territory should vote on whether to allow slavery

Zachary Taylor

Mexican War general and Whig president who opposed expanding slavery into the territories

Forty-niners

Gold seekers who rushed to California during the 1849 Gold Rush

“Slavery follows the flag”

Southern argument that slaveholders could bring enslaved people into any U.S. territory

Compromise of 1850

Laws admitting California as free, strengthening the Fugitive Slave Act, and using popular sovereignty in new territories

Harriet Beecher Stowe

Author of Uncle Tom’s Cabin, which increased Northern opposition to slavery

Personal-liberty laws

Northern state laws protecting alleged fugitive slaves from being captured

Stephen Douglas

Illinois senator who championed popular sovereignty and wrote the Kansas-Nebraska Act

Gadsden Purchase

1853 land purchase from Mexico intended for a southern transcontinental railroad route

Ostend Manifesto

Secret U.S. plan to acquire Cuba as a potential slave state

Kansas-Nebraska Act

Law allowing popular sovereignty in Kansas and Nebraska, effectively repealing the Missouri Compromise

Know-Nothing Party

Anti-immigrant, anti-Catholic political party of the 1850s

“Bleeding Kansas”

Violent conflict between pro-slavery and anti-slavery settlers in Kansas

John Brown

Radical abolitionist who used armed resistance against slavery

Dred Scott v. Sanford

Supreme Court decision declaring that enslaved people were not citizens and Congress couldn’t ban slavery in territories

Abraham Lincoln

Rising Republican leader who opposed the expansion of slavery

Freeport Doctrine

Douglas’s claim that territories could limit slavery by refusing to pass laws protecting it