Study guide: Causes of the American Civil War

📋 Course Outline

1. Slavery and Economic Divisions
2. Failed Political Compromises
3. Expansion and Manifest Destiny
4. Moral Conflict and Sectionalism
5. Polarization, Lincoln, and Secession
6. Building and Evaluating the Essay

📅 Key Dates

1. 1787the Three-Fifths Compromise counted enslaved people as three-fifths of a person for representation, strengthening slaveholding states politically without giving enslaved people votes
2. 1803the Louisiana Purchase greatly expanded U.S. territory and created future debates about slavery’s status in the new lands
3. 1820the Missouri Compromise admitted Missouri as a slave state and Maine as a free state, while barring slavery in most Louisiana Purchase lands north of 36°30′
4. 1845John O’Sullivan popularized Manifest Destiny, the idea that the United States was destined to expand across the continent - John O'Sullivan, 1845
5. 1846-1848the Mexican-American War brought new western territories that intensified disagreement over free and slave territory
6. 1848-1849the California Gold Rush accelerated migration and California’s push toward statehood
7. 1850the Compromise of 1850 admitted California as a free state, but its strengthened Fugitive Slave Act angered many Northerners
8. 1854the Kansas-Nebraska Act used popular sovereignty to reopen territory to possible slavery and effectively overturned the Missouri restriction
9. 1854-1859proslavery and antislavery settlers fought over the future of Kansas in the violence known as Bleeding Kansas
10. 1857the Supreme Court ruled in Dred Scott that Congress could not prohibit slavery in federal territories

📖 1. Slavery and Economic Divisions

★ Must-know

📌 The North developed an industrial, wage-labor economy, while wealthy Southern plantation owners depended on enslaved labor and cotton exports.

• Southern slaveholders regarded slavery as essential to their wealth and political power, while the economic contrast made disputes about slavery’s future harder to settle.

Further detail

• 🔄 The cotton gin’s effects were:

  1. faster cotton processing
  2. greater profitability of cotton cultivation
  3. expansion of slavery

• Cotton plantations expanded across the Deep South, and New Orleans became a major trading port.

• Northern textile mills and merchants also profited from Southern cotton, so the economies were interdependent.

💡 Memory Hook

Northern wage labor contrasted with Southern enslaved plantation labor.

📖 2. Failed Political Compromises

📝 Essential Points

• Repeated compromises often postponed rather than solved the dispute, while contradictory policies and court rulings eroded trust in national institutions and made further compromise harder.

💡 Memory Hook

Compromises postponed disputes → trust in national institutions eroded.

📖 3. Expansion and Manifest Destiny

📝 Essential Points

• Each potential new state threatened the political balance in Congress, making westward expansion a source of repeated national crises and sometimes violence.

💡 Memory Hook

New territories reopened the slavery question → national crises.

📖 4. Moral Conflict and Sectionalism

★ Must-know

• In 1859, John Brown’s attempted antislavery uprising at Harpers Ferry heightened Southern fears.

• As sectionalism grew, loyalty to the North or South increasingly outweighed loyalty to the nation.

• Abolitionist activism exposed the moral conflict over slavery, and proslavery leaders viewed growing antislavery sentiment as a threat, deepening fear, resentment, and sectional polarization.

Further detail

• Frederick Douglass and William Lloyd Garrison publicly campaigned against slavery as abolitionists.

• In 1852, Harriet Beecher Stowe’s novel Uncle Tom’s Cabin spread antislavery sentiment. - Uncle Tom's Cabin

📌 Many Quakers and other Christians condemned slavery, while some Southern defenders invoked religion to justify it.

💡 Memory Hook

Abolitionists condemned slavery while Southern defenders invoked religion to justify it.

📖 5. Polarization, Lincoln, and Secession

★ Must-know

• In November 1860, Abraham Lincoln was elected president without carrying any slave state; he opposed slavery’s expansion, not immediate abolition in existing slave states.

• In December 1860, South Carolina seceded from the Union, followed by six more states before Lincoln’s inauguration.

• In April 1861, Confederate bombardment of Fort Sumter began the war, after which four additional states seceded.

• Slavery was the fundamental cause of the war; economic differences, westward expansion, failed compromises, and sectional hostility became explosive largely because of the dispute over slavery.

Further detail

• In 1854, the Republican Party grew in opposition to the expansion of slavery into western territories.

• In 1858, the Lincoln-Douglas debates publicized national disagreements over slavery’s expansion.

💡 Memory Hook

Lincoln’s election → secession → Fort Sumter → open war.

📖 6. Building and Evaluating the Essay

★ Must-know

• A strong essay introduction defines the debate and states a judgement, body paragraphs develop a claim through Point, Evidence, Explain, and Link (PEEL), and the conclusion ranks the causes.

📌 The conclusion should distinguish long-term root causes such as slavery and sectional divisions, accelerators such as territorial expansion and failed compromises, and immediate triggers such as the election, secession, and Fort Sumter.

Further detail

• Useful judgement phrases include:
  • This was significant because…
  • However, this factor alone cannot explain…
  • More fundamentally…
  • It intensified existing tensions by…
  • Unlike the long-term causes, this was the immediate trigger.

💡 Memory Hook

PEEL: Point → Evidence → Explain → Link.