Period 5: 1844–1877

What this unit covers

The topics below follow the published US History course framework for Unit 5. This unit is worth 10–17% of the exam, so budget your time against that rather than against how long the unit takes to teach.

Lessons in this unit

• Manifest Destiny & the Sectional Crisis14 min · 3 objectivesExplain how Manifest Destiny drove territorial expansion in the 1840s · Analyze how new territories reignited the conflict over slavery · Trace the failure of political compromises to resolve sectional tensions
• The Civil War14 min · 3 objectivesIdentify the immediate causes of secession and the outbreak of war · Explain how the Emancipation Proclamation transformed the war’s purpose · Analyze the Union’s advantages and the war’s effect on the nation
• Reconstruction & Its Collapse13 min · 3 objectivesCompare presidential and congressional (Radical) Reconstruction · Explain the significance of the Reconstruction Amendments · Analyze why Reconstruction ended and what its legacy meant for Black Americans
• The Compromises Unravel, 1846–186115 min · 3 objectivesTrace the sequence from the Wilmot Proviso to secession · Explain popular sovereignty and why it produced violence in Kansas · Analyze Dred Scott and the collapse of the second party system
• Emancipation as a Process15 min · 3 objectivesExplain how the war's aims shifted from union to emancipation · Analyze the actual legal reach of the Emancipation Proclamation · Describe the role of Black soldiers and self-emancipation
• The Constitutional Revolution: The Reconstruction Amendments14 min · 3 objectivesState precisely what each Reconstruction amendment did · Explain how Black Codes and Southern resistance shaped Congressional Reconstruction · Analyze how Supreme Court rulings narrowed the amendments

Every term in Unit 5

All 37 terms we publish for Period 5: 1844–1877, with definitions. Reading them through is the fastest way to find the ones you cannot define — then drill those in cram mode until you can produce them without the prompt.

Popular sovereignty

Doctrine that territory settlers vote on slavery; used in the Compromise of 1850 and Kansas-Nebraska Act.

Dred Scott v. Sandford (1857)

Taney Court ruling that Black Americans were not citizens and that Congress could not bar slavery from federal territories. Significance: voided the Missouri Compromise line, undermined popular sovereignty, radicalized Northern opinion, and made Republican victory in 1860 more likely.

Emancipation Proclamation (1863)

Lincoln’s wartime order declaring free all enslaved people in areas still in rebellion. Significance: redefined the war as a war against slavery, blocked European recognition of the Confederacy, and authorized the enlistment of Black soldiers; the Thirteenth Amendment (1865) actually abolished slavery.

Mexican-American War (1846–48)

Ended with the Mexican Cession, adding the Southwest and California — and reopening the question of slavery in the territories.

Wilmot Proviso (1846)

Proposal to bar slavery from any land taken from Mexico. Never passed the Senate, but it split parties along sectional rather than partisan lines.

Compromise of 1850

California free, a stronger Fugitive Slave Act, the slave trade ended in DC, popular sovereignty in Utah and New Mexico. Bought a decade and enraged the North.

Fugitive Slave Act (1850)

Compelled Northern citizens and officials to help capture escapees and denied the accused a jury trial. Made Northerners complicit and radicalized opinion.

Uncle Tom's Cabin (1852)

Stowe's novel dramatized slavery's cruelty for a mass Northern audience and hardened sectional feeling.

Kansas-Nebraska Act (1854)

Repealed the Missouri Compromise line in favor of popular sovereignty. Destroyed the Whigs, birthed the Republicans and produced "Bleeding Kansas".

Lincoln-Douglas debates (1858)

Senate debates over slavery in the territories; Douglas's Freeport Doctrine kept Illinois but cost him Southern support in 1860.

John Brown's raid (1859)

Failed attempt to spark a slave uprising at Harpers Ferry. Brown became a martyr in the North and proof of Northern intentions in the South.

Election of 1860

Lincoln won with under 40% of the popular vote and no Southern electoral votes, prompting secession before he took office.

Gettysburg and Vicksburg (1863)

Twin turning points: Lee's invasion was broken in the East and the Union split the Confederacy by taking the Mississippi.

Gettysburg Address

Recast the war as a test of whether a nation "conceived in liberty" could endure, tying the Union cause to the Declaration's equality clause.

Thirteenth Amendment (1865)

Abolished slavery except as punishment for crime — an exception later exploited through convict leasing.

Fourteenth Amendment (1868)

Birthright citizenship, due process and equal protection against the states. The constitutional basis of most later civil-rights litigation.

Fifteenth Amendment (1870)

Barred denying the vote on grounds of race. Its silence on literacy, property and poll taxes left the loopholes the South later used.

Freedmen's Bureau

Federal agency providing food, legal aid, labor contracts and schools to freedpeople. Founded several HBCUs; underfunded and shut down in 1872.

Black Codes

Southern laws restricting freedpeople's movement, contracts and property, recreating conditions close to slavery. Provoked Congressional Reconstruction.

Radical Reconstruction

Congress divided the South into military districts and required Black suffrage and Fourteenth Amendment ratification for readmission.

Sharecropping

Tenants farmed for a share of the crop, borrowing against it at high interest. Debt peonage kept freedpeople bound to land they did not own.

Ku Klux Klan

Paramilitary terror organization using violence to suppress Black voting and Republican organizing; targeted by the Enforcement Acts.

Compromise of 1877

Hayes took the presidency, federal troops left the South and Reconstruction ended, clearing the way for disenfranchisement and Jim Crow.

Mexican Cession (1848)

The land taken under the Treaty of Guadalupe Hidalgo — present-day California, Nevada, Utah and more — and the territory whose status the political system could not resolve.

Free Soil Party

Antislavery party of 1848 opposing slavery's extension into the territories, whose voters formed a core of the later Republican coalition.

Bleeding Kansas

Guerrilla war after the Kansas-Nebraska Act: fraudulent elections, the sack of Lawrence, Pottawatomie. Showed popular sovereignty could not settle the question peacefully.

Caning of Charles Sumner (1856)

Representative Preston Brooks beat Senator Sumner unconscious on the Senate floor after an antislavery speech. Each region treated its own man as the hero.

Crittenden Compromise (1860)

Last-ditch proposal to extend the Missouri line to the Pacific and protect slavery by amendment. Lincoln rejected it, since it conceded the one point Republicans existed to hold.

Contraband policy

Butler's classification of escapees as enemy property put to Union use, ratified by the Confiscation Acts — the legal improvisation through which emancipation began.

Confiscation Acts (1861, 1862)

Authorized seizure of property including enslaved people used to aid the rebellion, then freed those of disloyal owners — congressional emancipation before the Proclamation.

Self-emancipation

The roughly half a million enslaved people who walked to Union lines, forcing emancipation onto the national agenda ahead of Lincoln's own timetable.

United States Colored Troops

About 180,000 Black soldiers, a tenth of the Union army, serving at lower pay until 1864 and facing massacre rather than capture. Their service became an argument for citizenship.

54th Massachusetts

Black regiment whose assault on Fort Wagner put Black valor into the Northern press, strengthening the political case that would become the Fourteenth Amendment.

Wade-Davis Bill (1864)

Radical plan requiring an ironclad oath from a majority of voters before readmission. Lincoln pocket-vetoed it, marking the presidential-congressional split over Reconstruction.

Presidential Reconstruction

Johnson's lenient terms — an oath, ratification of the Thirteenth Amendment, repudiation of Confederate debt — which produced Black Codes and returned Confederate officials to Congress.

Impeachment of Andrew Johnson (1868)

House impeachment over the Tenure of Office Act after Johnson obstructed Congressional Reconstruction; the Senate acquitted him by one vote.

Slaughter-House Cases (1873)

Read the Fourteenth Amendment's privileges-and-immunities clause so narrowly as to render it nearly useless — the first major judicial narrowing of Reconstruction.

What examiners penalize here

• When evaluating Reconstruction, avoid calling it a total failure. Argue the nuance: it failed to secure immediate equality, **but** the 13th, 14th, and 15th Amendments became the legal foundation for the twentieth-century civil rights movement. That "seeds for the future" framing earns complexity points.
• Reconstruction essays score best when they distinguish **formal change from enforced change**. The amendments were a genuine constitutional revolution; the withdrawal of enforcement is what made them ineffective for eighty years. Saying "Reconstruction failed" without that distinction loses the analytical point — the text survived, and it is what the 1950s and 60s built on.

Practice US History

Our practice bank is drawn from across the whole course rather than filtered to one unit, which is closer to how the exam asks anyway — it will not tell you which unit a question is testing.

Questions about this unit

All 9 units of AP United States History

1. Unit 1 · Period 1: 1491–1607
2. Unit 2 · Period 2: 1607–1754
3. Unit 3 · Period 3: 1754–1800
4. Unit 4 · Period 4: 1800–1848
5. Unit 5 · Period 5: 1844–1877
6. Unit 6 · Period 6: 1865–1898
7. Unit 7 · Period 7: 1890–1945
8. Unit 8 · Period 8: 1945–1980
9. Unit 9 · Period 9: 1980–Present