SSUSH8 Vocabulary Chart — Slavery, Sectionalism, and Westward Expansion

Missouri Compromise (1820)

Federal law admitting Missouri as a slave state and Maine as a free state while banning slavery north of 36°30′ in the Louisiana Territory.

Temporarily preserved sectional balance but institutionalized the geographic divide over slavery; first major political line between free and slave regions. [8a]

36°30′ Line

Latitude boundary created by the Missouri Compromise to determine future slave or free territories.

Became the symbolic frontier between liberty and bondage; its 1854 repeal reignited sectional violence. [8a]

James K. Polk

11th U.S. President (1845-1849) who expanded U.S. territory through Texas annexation, Oregon settlement, and victory in the Mexican War.

Fulfilled Manifest Destiny but reignited the slavery-expansion debate in every new territory. [8b]

Manifest Destiny

Belief that the U.S. was divinely destined to expand westward to the Pacific.

Unified Americans under expansionist ideals while justifying conquest, Native removal, and renewed slavery conflicts. [8b]

Texas Annexation (1845)

Admission of the Republic of Texas to the Union as a slave state.

Triggered war with Mexico and heightened Northern fears of a “slave power” agenda. [8b]

Oregon Boundary Settlement (1846)

Treaty with Britain setting the U.S.–Canada border at 49° N.

Achieved peaceful expansion but showed sectional priorities—southern focus on Texas, northern push for Oregon. [8b]

Mexican–American War (1846–1848)

Conflict between the U.S. and Mexico over Texas and western territory.

Added vast lands and reignited debate over slavery’s expansion; training ground for future Civil War leaders. [8c]

Treaty of Guadalupe Hidalgo (1848)

Treaty ending the Mexican War; Mexico ceded California and the Southwest to the U.S.

Made the U.S. a continental power but reopened the slavery question in the new territories. [8c]

Mexican Cession

Land ceded to the U.S. after 1848 (CA, NV, UT, NM, AZ parts).

Intensified sectionalism as both regions sought to control the new territories. [8c]

Wilmot Proviso (1846)

Proposed law banning slavery in lands won from Mexico; failed in Senate.

Exposed deep sectional divisions and previewed the fall of national parties. [8c]

California Gold Rush (1848–49)

Mass migration west after gold discovery at Sutter’s Mill.

Rapid population growth forced the Compromise of 1850 and reopened the free/slave balance debate. [8d]

Compromise of 1850

Five-part deal: CA free, UT/NM popular sovereignty, stronger Fugitive Slave Act, no slave trade in D.C.

Eased tension briefly but enraged both sides; strengthened Northern abolitionism. [8d]

Popular Sovereignty

Letting territorial settlers vote on slavery.

Tried to democratize compromise but failed violently in Kansas. [8d–8e]

Fugitive Slave Act (1850)

Required return of escaped enslaved people and penalized non-enforcers.

Brought slavery’s brutality northward and unified Northern opposition. [8d]

Kansas–Nebraska Act (1854)

Created KS and NE territories under popular sovereignty; repealed 36°30′ line

Shattered national unity, sparked Bleeding Kansas, and birthed the Republican Party. [8e]

Bleeding Kansas (1854–56)

Violent conflict between pro- and anti-slavery settlers.

Proved that democracy could not contain moral conflict; foreshadowed civil war. [8e]

Dred Scott v. Sandford (1857)

Supreme Court ruling denying Black citizenship and Congress’s power to ban slavery in territories.

Invalidated prior compromises and radicalized both North and South. [8e]

Republican Party (1854)

Political coalition opposing slavery’s expansion.

Replaced the Whigs and sectionalized national politics; platform led to Lincoln’s victory. [8e]

John Brown’s Raid (1859)

Armed attempt to start a slave uprising at Harper’s Ferry, VA.

Polarized the nation—martyr to the North, menace to the South. [8e]

Election of 1860

Lincoln’s victory on a free-soil platform without Southern votes.

Proved the Union’s political fracture and triggered secession. [8e]

Secession (1860–61)

Withdrawal of eleven Southern states forming the Confederacy.

Final break of sectional compromise; immediate cause of the Civil War. [8e]