The American Civil War lasted from 1861 to 1865 and was fought between the Union and the eleven southern states that formed the Confederacy. Slavery and its expansion were central to the dispute, though historians weigh the other causes differently. This page sets out the facts, then shows how to sort causes and read opposing sources.
It is a unit in core option A study pathways. Your own syllabus year decides the depth required, so check the Cambridge page. For the causal wording used here, see qualified causal language.
What are the key dated facts?
These can be checked in standard reference works.
- 1854: the Kansas-Nebraska Act reopened the question of slavery in new territories.
- 1857: the Supreme Court’s Dred Scott decision ruled against the rights of a man who had sued for his freedom.
- 1859: John Brown led a raid on the federal arsenal at Harpers Ferry.
- November 1860: Abraham Lincoln was elected president.
- December 1860 to 1861: South Carolina, then ten other southern states, left the Union.
- April 1861: fighting began at Fort Sumter.
- 1 January 1863: the Emancipation Proclamation took effect.
- April 1865: General Lee surrendered at Appomattox.
- December 1865: the Thirteenth Amendment, ending slavery, was ratified.
How can you sort the causes?
Sort each cause as long-term, trigger or consequence, and give one dated example.
| Cause | Type | Dated example (fact) |
|---|---|---|
| Disagreement over slavery’s spread | Long-term | Kansas-Nebraska Act, 1854 |
| States’ rights arguments | Long-term | Used in southern arguments for secession in 1860 to 1861 |
| Economic differences between regions | Long-term | Different economies in the northern and southern states |
| Lincoln’s election | Trigger | November 1860 |
| Dispute over Fort Sumter | Trigger | April 1861 |
Historians disagree about how much weight each deserves. That is an interpretation, so your answer should give a reason for your ranking.
Worked example: two invented opposing sources
Invented extract A (for practice, not a real document): “The new government threatens our way of life, and we must protect our rights as a state.” (A fictional speech by a southern politician, 1860.)
Invented extract B (for practice, not a real document): “A union cannot survive if any state may leave it whenever it pleases.” (A fictional pamphlet by a northern writer, 1861.)
Step 1, whose viewpoint? A defends a state’s right to act independently. B defends the unity of the nation.
Step 2, what do they show? Both show how supporters of each side framed the dispute, using the language of rights and union.
Step 3, what do they not show? Neither mentions slavery directly. That does not prove it was unimportant, because other evidence from the period links the secession decisions to slavery. A source’s silence is not proof.
Step 4, a careful statement. “Extracts A and B show that rights and union were central arguments for each side, but other evidence is needed to judge the role of slavery.”
The mistake to watch for
A student writes: “The war was about states’ rights, because the speech says so.”
This treats one source’s framing as the whole truth.
The correction is to compare it with other evidence, such as the secession declarations of several states. It also separates what people said from what historians conclude: “States’ rights was an argument used by supporters of secession. The wider evidence links it closely to the defence of slavery.”
Check yourself
1. Is Lincoln’s election a long-term cause or a trigger?
Show answer
A trigger, because it was an immediate event in November 1860 that led to secession, set against long-term disagreements.
2. Give two consequences of the war.
Show answer
Any two of: Union victory in 1865; the legal end of slavery by the Thirteenth Amendment in December 1865; a very large number of deaths; the period of Reconstruction.
3. Why is “the speech does not mention slavery, so slavery was not a cause” a weak argument?
Show answer
Because one source’s silence does not show that something was unimportant. Other evidence from the same period must be checked before drawing the conclusion.
Where this leads next
Practise the skills in the integrated practice set. For a different kind of unit, read about nineteenth-century overseas empires.
Source questions often go wrong at the point where a student stops comparing. A teacher in online one-to-one History tuition can practise that step with your own extracts.