In August 1846, a few months into the war with Mexico, a Pennsylvania congressman named David Wilmot proposed that slavery be banned in any land the United States won in it. It passed the House, failed in the Senate, and asked the question that would dominate the next fifteen years: when the country grew, would slavery grow with it?
This lesson covers Period 5 of AP US History, from 1844 to 1877.
The big themes
- Expansion. The US added Texas, Oregon and the Mexican Cession, and drew migrants from Ireland, Germany and China.
- Slavery in the territories. Every new territory reopened the fight between free labor and slave labor.
- Compromise, then failure. Each attempt to settle the question made the conflict worse.
- War and Reconstruction. Union victory ended slavery and secession but left citizenship and federal power unsettled.
Manifest Destiny and the war with Mexico
In 1845 the editor John O'Sullivan is credited with naming the belief that the US was meant to spread across the continent: Manifest Destiny. Texas, independent since 1836, was annexed that year, and the 1846 Oregon Treaty split the Northwest with Britain at the 49th parallel. Fighting broke out in land between the Nueces River and the Rio Grande that both the US and Mexico claimed, and war followed. The Treaty of Guadalupe Hidalgo (1848) gave the US California and much of the Southwest. Frederick Douglass and other critics saw it as a grab for slave territory. Mexicans and American Indians in the new lands lost land and self-sufficiency.
Compromises that didn't hold
After the Gold Rush, California asked to join as a free state. The Compromise of 1850 admitted it, left slavery in Utah and New Mexico to their settlers, banned the slave trade in Washington, D.C., and passed a harsher Fugitive Slave Act. That act, and Uncle Tom's Cabin (1852), deepened Northern anger.
In 1854 the Kansas–Nebraska Act let settlers in those territories vote on slavery, overturning the Missouri Compromise line. Rival settlers rushed in, and Kansas turned violent. The Whigs collapsed, the anti-Catholic Know-Nothings rose briefly, and the new Republican Party formed to stop slavery's spread. In Dred Scott v. Sandford (1857) the Supreme Court ruled that Black Americans were not citizens and that Congress could not ban slavery in the territories. The ruling inflamed the debate instead of ending it.
Secession and the Civil War
In 1860 Lincoln won the presidency on a free-soil platform without a single Southern electoral vote. South Carolina seceded that December, and six more states followed. After Confederate forces fired on Fort Sumter in April 1861, four more joined them. The North had more people, factories and railroads; the South had able generals and early victories. Lincoln's first aim was saving the Union. The Emancipation Proclamation, effective January 1, 1863, made ending slavery a war aim, freed enslaved people in areas in rebellion, and began large-scale recruitment of Black soldiers. Victories at Gettysburg and Vicksburg in July 1863 turned the war, and Lee surrendered at Appomattox in April 1865.
Reconstruction
The 13th Amendment (1865) abolished slavery. After Southern states passed Black Codes, Congress added the 14th Amendment (1868), which defined citizenship and promised equal protection, and the 15th (1870), which barred denying the vote by race. Radical Republicans placed most of the former Confederacy under military rule, and the House impeached President Andrew Johnson, who escaped conviction in the Senate by one vote. Black men voted and held office; in 1870 Hiram Revels of Mississippi became the first African American senator. But most freed people never got land, and sharecropping kept many in debt. Klan violence and the North's fading will wore Reconstruction down. After the disputed 1876 election, Rutherford B. Hayes took office and federal troops left Southern statehouses.
Common mistakes students make
- Saying the Emancipation Proclamation freed every enslaved person. It covered areas in rebellion; the 13th Amendment ended slavery everywhere.
- Mixing up 1850 and 1854. Both used popular sovereignty, but only Kansas–Nebraska overturned the Missouri Compromise line.
- Saying the North fought to end slavery from the start. Lincoln's first aim was saving the Union; emancipation became a war aim in 1863.
- Treating the Free-Soil movement as abolitionism. Many free-soilers wanted the West kept for white free labor, not an end to slavery in the South.
Frequently asked questions
What years does APUSH Period 5 cover?
Period 5 runs from 1844 to 1877, from Polk's election to the Compromise of 1877. The Course and Exam Description weights it at 10–17% of the exam.
Why did the Compromise of 1850 fail?
Its Fugitive Slave Act angered the North, and the Kansas–Nebraska Act reopened the territories question in 1854.
What did the Reconstruction amendments do?
The 13th abolished slavery, the 14th made formerly enslaved people citizens with equal protection, and the 15th barred denying the vote by race.
Why did Reconstruction end?
Southern resistance, including violence, combined with the North's fading commitment.
Try it
Say each answer before you flip the card. Then line up 1850, 1854 and 1857: three attempts to settle slavery in the territories, each one making the next fight worse. What changed, and why then?
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