Slavery: Cause and Catalyst 

of the Civil War

U.S. Department of the Interior

National Park Service

Southeast Region

NPS/CUMBERLAND GAP NHP

NPS COLLECTION

What caused the Civil War?

A number of issues ignited 

the Civil War: states’ rights, 

the role of the federal government, 

the preservation of the Union,

 the economy; but all were 

inextricably bound to 

the institution of slavery.
LIBRARY OF CONGRESS

Alexander Stephens, 

Vice President 

of the Confederate 

States of America

The Context for Conflict

The role of slavery in bringing on the Civil War has been hotly 

debated for decades. One important way of approaching the issue 

is to look at what contemporary observers had to say. In March 1861, 

Alexander H. Stephens, Vice President of the Confederates States 

of America, was quoted in the Savannah Republican:

“The new constitution has put at rest, forever, all the agitating 

questions relating to our peculiar institution African slavery as it 

exists amongst us, the proper status of the negro in our form of 

civilization. This was the immediate cause of the late rupture and 

present revolution. Jefferson in his forecast, had anticipated this, as 

the ‘rock upon which the old Union would split.’ He was right. What 

was conjecture with him, is now a realized fact.

“[Our] foundations are laid, its cornerstone rests, upon the great

truth that the negro is not equal to the white man; that slavery, 

subordination to the superior race is his natural and normal 

condition.”

Savannah Republican, March 21, 1861 

 

Today, most professional historians agree with Stephens that slavery 

and the status of African Americans were at the heart of the crisis 

that plunged the U.S. into a civil war from 1861 to 1865. That is not to say 

the average Confederate soldier fought to preserve slavery or the average 

Union soldier went to war to end slavery. Some fought on moral grounds. 

Some fought because they felt their way of life and prosperity were 

threatened. Others fought to preserve the Union. Soldiers fight for many 

reasons—notably to stay alive and support their comrades in arms. The 

North’s goal in the beginning was the preservation of the Union, not 

emancipation. For the 180,000 African Americans who ultimately served 

the U.S. in the war, however, emancipation was the primary aim. NPS/HUGH BROWN

Among the many who did not share 

Alexander Stephen’s beliefs on racial 

inequality was the firebrand Congressman 

from Pennsylvania, Thaddeus Stevens, 

who said, “I can never acknowledge the right 

of slavery” and chose to be buried in a 

remote cemetery that would also include 

African Americans, so his principles 

would be upheld, even in death.

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NPS/RICHARD SCHLECHT

The roots of the crisis over slavery that gripped the nation in 1860-1861 go 

back well before the nation’s founding. In 1619, slavery was introduced to 

Virginia, when a Dutch ship traded African slaves for food. Unable to find 

cheap labor from other sources, white settlers increasingly turned to slaves 

imported from Africa. By the early 1700s, in British North America, slavery 

generally meant African slavery. Southern plantations using slave labor pro-

duced the great export crops—tobacco, rice, forest products, and indigo—that 

made the American colonies prosperous. Many Northern merchants made 

their fortunes either in the slave trade or by exporting the products of slave 

labor. African slavery was central to the development of British North America. 

Although slavery existed in all 13 

colonies at the start of the American 

Revolution in 1775, a number of 

Americans (especially those of 

African descent) sensed the 

contradiction between the 

Declaration of Independence’s 

ringing claim of human equality 

and the existence of slavery. 

Reacting to that contradiction, 

Northern states decided to phase 

out slavery following the Revolution. 

The future of slavery in the South 

was debated, and some held 

out the hope it would eventually 

disappear there as well. 

We hold these truths to be self-evident, that all men are created equal, 

that they are endowed by their Creator with certain unalienable Rights, 

that among these are Life, Liberty, and the Pursuit of Happiness. 

United States Declaration of Independence

Slave ship 

bringing Africans 

to Jamestown, 

Virginia

23
Slavery and the Economy 

All realistic hope slavery might eventually die out in the South ended

when Massachusetts native Eli Whitney invented the cotton gin—a simple 

machine that enabled textile mills to use the type of cotton grown in most 

of the South. At the same time, the world demand for cotton exploded.

By 1840, cotton produced in the American South earned more money than 

all other U.S. exports combined. Many white Southerners came to believe 

cotton could be grown only with slave labor. Over time, most took for 

granted that their prosperity, even their way of life, was inseparable from 

African slavery.

Slavery was not the only source of dispute. The North and South were very 

different in nature, and wanted different things from their government.

In the North, society was fast becoming industrial. Immigrants in search

of work were arriving by the thousands. In addition, women began to

leave the farms seeking opportunity in the cities. Immigrants and women 

provided an abundant source of inexpensive labor to fuel the factories. 

Industrialization increased the amount of textiles produced and therefore, 

the demand for more slave labor. Entrepreneurs looking to develop these 

new industries demanded protection from the cheap European imports.

Women and immigrants 

at New England mills 

(Homer Lithograph)

The cotton gin 

greatly increased 

the amount of cotton 

that could be processed 

and therefore the 

demand for more 

slave labor. 

NPS/RICHARD SCHLECHT

NPS/LOWELL NHP

45
Slave quarters at 

Melrose Estate.

NPS/NATCHEZ NHP

The South, on the other hand, remained a region of small towns and large 

plantations. The great cotton empire depended on slave labor and cheap 

European imports. Southerners began to fear that if the North ever gained 

control in Congress, it would create taxes on imports, known as tariffs, 

which would ruin the South.

John C. Calhoun, Vice President under John Quincy Adams and Andrew 

Jackson, was among the first to voice this concern. Though he opposed 

secession, Calhoun argued that a state could protect its interests by simply 

nullifying any act by the Federal government it considered unconstitutional 

and unfair. Southerners began to rely on the concept of states’ sovereignty 

as a means of self-protection.

Formerly enslaved woman, 

Jane Johnson at Melrose 

Estate, Natchez, Mississippi, 

circa 1905

NPS/NATCHEZ NHP

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Slavery and the Constitution 

When the U.S. Constitution was written in 1787, the interests of 

slaveholders and those who profited from slavery could not be ignored. 

Although slaves could not vote, white Southerners argued slave labor 

contributed greatly to the nation’s wealth. The Constitution, therefore, 

provided for counting each slave as 3/5 of a person in the census for the 

purposes of representation in Congress and the electoral college. The 

clause gave the South a role in the national government far greater than 

representation based on its free population alone would have allowed. 

Although the Constitution did not use the term “slavery,” Article IV 

provided for the return of escaping persons “held to service or labor” 

such as fugitive slaves. Article I provided that the slave trade would end

20 years after the Constitution was ratified, which was in 1808. 

The Constitution left many questions about slavery unanswered, in 

particular, the question of slavery’s status in any new territory acquired 

by the U.S. The failure to deal forthrightly and comprehensively with 

slavery in the Constitution guaranteed future conflict over the issue 

and was ultimately one of the primary catalysts for war. 

The war began because a compromise did not exist that could 

solve the difference between the free and slave states regarding 

the power of the national government to prohibit slavery in 

territories that had not yet become states. 

 –James McPherson, Historian

The issue was not the existence of slavery, but the extension of it. 

 –Dwight Pitcaithley, former Chief Historian

of the National Park Service

89
...I had a vision...I saw white spirits and black spirits 

engaged in battle, and the sun was darkened – the thunder 

rolled in the Heavens, and blood flowed in streams – and I 

heard a voice saying, “... such you are called to see, and let 

it come rough or smooth, you must surely bear it.” 

Nat Turner, enslaved man

Slavery and States’ Rights

The question of who had the power to allow or disallow slavery in the 

territories and the newly formed states—the federal government or the 

states—provoked a heated national debate that would last for decades, 

resulting in a number of compromises. 

The proposed admission of Missouri as a slave state in 1820, led to the 

Missouri Compromise. Under its terms, Maine was admitted as a free state 

at the same time Missouri came in as a slave state, maintaining the balance 

between slave and free. Additionally, Congress prohibited slavery in all 

western territories lying above Missouri’s southern boundary.

The Missouri Compromise quieted the agitation over slavery. But, Thomas 

Jefferson, in a letter to a friend, said that the compromise was “like a 

firebell in the night.” He also foretold that the institution of slavery was like 

holding a “wolf by the ears, and we can neither hold him, nor safely let him 

go.” True to his prediction, the anti-slavery movement, which had been 

around since before the Revolutionary War, gained strength, and became 

more vocal and more radical by the 1830s, calling for the immediate end to 

slavery. One of these radical abolitionists, William Lloyd Garrison, declared: 

Enslave the liberty of but one human being and the liberties of 

the world are put in peril... I will be as harsh as truth, and 

uncompromising as justice... I am in earnest, I will not equivocate, 

I will not excuse, I will not retreat a single inch, and I will be heard.

The firebell in the night that Jefferson predicted went off when Nat Turner, 

an enslaved man in Southampton County, Virginia, believed that he was 

called by God in a vision to initiate a slave revolt. He hoped it would spread 

into a massive uprising. Starting with a few trusted fellow slaves, Turner 

began his rebellion on April 21, 1831. Other enslaved and free blacks joined, 

eventually numbering about 70 rebels. During the revolt, some 60 whites 

were killed. The retaliation was swift and harsh. Local militias and 

detachments from the American naval fleet docked in Norfolk, numbering 

about 3000 men, captured and executed 56 blacks. Another 100-200 blacks 

The capture of Nat Turner

©STOCK MONTAGE

©STOCK MONTAGE

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©JERRY PINKNEY

LIBRARY OF CONGRESS

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The Underground Railroad 

was a vast network of people 

who helped fugitive slaves 

escape to the North and to 

Canada. It was not run by any 

single organization or person. 

Rather, it consisted of many 

individuals, such as Harriet 

Tubman and Sojourner Truth—

some whites but predominantly 

blacks—who knew only of the 

local efforts to aid fugitives and 

not of the overall operation. 

Still, it effectively moved 

hundreds of thousands of slaves 

northward each year.

In 1853, a free black man, upon entering the state of 

Maryland, was sold into slavery and died trying to escape. 

In a letter to the leader of the Underground Railroad 

movement in Philadelphia, African American woman

and Anti-Slavery Society organizer, Frances Harper wrote: 

Upon that grave I pledge myself to the Anti-Slavery cause.

were killed during the retaliation. Nat Turner’s Revolt planted fear 

throughout the South. The Virginia General Assembly passed laws 

that made it unlawful to teach slaves or free blacks to read or write or 

to hold religious services, in which a white minister was not present. 

Other states followed Virginia’s lead. 

Later, the U.S. victory in the Mexican War of 1846-1848 brought the 

nation vast new acreage in the West. Once again, the status of slavery 

in the territories became a hot issue. Congressman David Wilmot of 

Pennsylvania introduced legislation strictly prohibiting slavery in any 

of the new lands. The bill failed to pass and the issue was argued 

furiously for the next fifteen years. 

A new agreement, the Compromise of 1850, became necessary 

when California sought to join the Union. The compromise admitted 

California as a free state, included a stronger fugitive slave law, 

assured Congress would not interfere with the interstate traffic in 

slaves in the South, and prohibited the slave trade in the District of 

Columbia. As is usually the case with compromises, neither side was 

pleased, but both accepted it, hoping the law would finally settle the 

slavery issue. It didn’t. Also in 1850, the area of present-day Arizona 

and New Mexico was established by Congress as the New Mexico 

Territory. While the territory was below the line established with the 

Missouri Compromise, Congress remained silent on whether or not 

slavery would be allowed in the territory. 

The passage of the Fugitive Slave Law in 1850 

incited great outrage. Commissioners received 

twice as much money for returning a slave to the 

South than for freeing them. This heightened 

Northern sympathy toward the runaway slave and 

caused great expansions in the existing vigilance 

and resistance movements. Organizations 

like the Anti-Slavery Society, spearheaded by both 

men and women, staged lectures and provided 

shelter, money, transportation, and services for 

slaves, to escape along the Underground Railroad. 
With tensions at a fevered pitch, Harriet Beecher Stowe published her 

novel Uncle Tom’s Cabin in 1852, describing the atrocities of slave life. 

The book sold 300,000 copies in its first year and became the second 

best-selling book of the 19th century, following the Bible. 

The novel’s popularity roused intense new resentment in the South. 

Then, in 1854, passage of the Kansas-Nebraska Act invoked the concept 

of “popular sovereignty” which gave the people of each territory choosing 

to pursue statehood, the right to decide whether or not to allow slavery. 

Pro- and anti-slavery factions turned the Kansas Territory into a bloody 

battleground. 

Settlers from the North were determined to make Kansas a free state. 

Southern settlers were equally determined to make it a slave state. 

Missouri’s Border Ruffians came across the border to intimidate 

free-soilers and raid abolitionist towns. Some Northerners shipped in 

boxes of rifles, known as “Beecher’s Bibles.” (Filled with antislavery fervor, 

the Reverend Henry Ward Beecher had once said there might be situations 

where a gun was more useful than a Bible.) John Brown and his followers 

started their bloody fight against slavery, killing pro-slavery sympathizers

in Kansas.

Back in Washington, D.C., tempers 

flared. After addressing “the crime 

against Kansas,” Senator Charles Sumner 

from Massachusetts was attacked 

with a cane and beaten unconscious 

on the Senate floor. Senator Toombs 

from Georgia announced he would 

one day auction slaves on Boston 

Common itself. In Alabama, Secessionist 

William Lowndes Yancey argued angrily 

that the South would never find 

happiness until it left the Union and 

became an independent nation.

Harriet Beecher Stowe’s

novel, Uncle Tom’s Cabin, 

incited anger in the South.

NPS/RICHARD SCHLECHT

Pro-Slavery 

proponents killed 

five people and 

wounded six others in 

the Marais Des Cygnes 

Massacre in Kansas 

as a result of the 

tensions caused by the 

Kansas-Nebraska Act.

NPS/HANDCOLORED RICHARD SCHLECHT

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Preston Brooks canes Senator Sumner 

unconscious on the Senate Floor in the heated 

dispute over the Kansas-Nebraska Act.

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©JIM WASSEL

Imagine the thoughts of John Brown 

and his anti-slavery followers in the 

captured engine house as they ponder 

their fate while a massive military 

detachment forms outside.

The Politics of Unrest

The Republican Party was organized as a direct response to the 

Kansas-Nebraska Act. The Republicans made opposition to the extension 

of slavery in the territories their chief issue. Inevitably, the party aroused 

deep anger in the South. Attitudes in the two sections of the nation 

continued to harden into the late 1850s.

Then, in 1857, Dred Scott, an enslaved man who was taken by his owner,

an Army surgeon, into Illinois and Wisconsin Territory (later Minnesota) 

which were part of the Northwest Territory in which slavery was 

prohibited, sued for his freedom. The U. S. Supreme Court decided that 

Americans of African descent—whether enslaved or free—were not U.S. 

citizens and did not have the right to sue. The Court also found the 

Missouri Compromise unconstitutional, ruling that the federal 

government did not have the authority to prohibit slavery in the territories. 

Two years later, the powder keg ignited. John Brown, with a handful of 

followers, attempted to seize the Federal arsenal at Harpers Ferry, hoping 

to use the weapons stored there to incite a slave insurrection in the South. 

He managed to capture an engine house which he held overnight. 

However, the next morning, a detachment of U.S. Marines, led by army 

Colonel Robert E. Lee overran the building. Brown was quickly tried, 

convicted of treason, and hanged. After this raid, the hope of a peaceful 

solution to the problem of slavery seemed more and more remote. 

If it is deemed necessary that I should forfeit my life for the furtherance 

of the ends of justice, and mingle my blood further... with the blood of 

millions in this slave country whose rights are disregarded by wicked, 

cruel, and unjust enactments—I submit; so let it be done. 

John Brown, Abolitionist, at his court hearing

Enslaved man, Dred 

Scott sues unsuccessfully 

for his freedom.

NPS/RICHARD SCHLECHT

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The question of slavery, and particularly slavery in the 

territories, dominated the presidential election of 1860. The 

recently formed Republican Party emerged as the advocate for 

abolishing slavery in the territories. Abraham Lincoln was the 

party candidate. The Democratic Party, which had dominated 

politics in the 1850s, split along sectional lines, with Northern 

Democrats nominating Stephen A. Douglas, and adopting a 

platform of extending popular sovereignty to the territories. 

The Southern Democrats nominated John C. Breckenridge, 

and their platform advocated the protection of slavery where it 

existed and in the territories. Not happy with any of the above 

options, another party, the Constitutional Union Party, made up 

of remnants of the Whig and other earlier parties, nominated 

John Bell as its candidate. It’s platform advocated compromise 

on the issue to slavery to save the Union and the Constitution. 

Though he didn’t receive a majority of the popular vote, 

Lincoln gained a solid majority in the Electoral College. He 

won the election by carrying most Northern states and the 

western states of California and Oregon, while failing to 

receive a single electoral vote in the Deep South, where in ten 

states he was not on the ballot. 

Spurred by South Carolina, the states of the Deep South 

concluded a limitation on slavery in the territories was 

the first step toward a total abolition of its “peculiar 

institution.” Expecting the worst, the South Carolina 

legislature remained in session waiting for the election to 

be held. Immediately upon seeing the results, representatives 

called for a special state convention in December, which 

voted unanimously for the state to secede from the Union.

One by one, six other states—Mississippi, Florida, Georgia, 

Alabama, Louisiana, and Texas—also left the Union, calling 

their new country the Confederate States of America and 

electing Jefferson Davis as its president.

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Following Lincoln’s election, the State of South 

Carolina votes to secede from the Union. 

 Jefferson Davis, 

President of 

the Confederate 

States of America

LIBRARY OF CONGRESS

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Lincoln hoped desperately to achieve a peaceful solution, but when

he decided to resupply the U.S. army troops at Fort Sumter in Charleston

Harbor in April of 1861, Confederate forces fired on the fort. Lincoln 

then asked for 75,000 volunteers to put down the rebellion. This 

prompted Virginia, North Carolina, Tennessee, and Arkansas to join 

the Confederacy. Civil war had come. 

There were many differences of opinion between the North and the South 

in 19th-century America. Differences over slavery were the only ones that 

could not be settled by peaceful means. Evidence from that time shows the 

secession of seven Deep South states was caused primarily by concerns 

over the future of slavery. When Mississippi seceded, she asserted that: 

Our position is thoroughly identified with the institution of slavery . . . 

Utter subjugation awaits us in the Union, if we should consent longer to 

remain in it. It is not a matter of choice, but of necessity. We must either 

submit to degradation, and to the loss of property worth four billions of 

money [the estimated total market value of slaves], or we must secede 

from the Union framed by our fathers, to secure this as well as every 

other species of property. NPS/FORT SUMTER NM

The Confederate attack 

on Fort Sumter in Charleston, 

South Carolina

The bullets that ripped through the 

US flag at Fort Sumter tore the fabric 

of the nation in half and shredded 

any hope for peaceful resolution.

NPS/FORT SUMTER NM

NPS/FORT SUMTER NM

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Fighting for Freedom

Though emancipation was the goal of the war for African Americans, 

President Lincoln insisted the conflict was not about slavery or civil 

rights, but an effort to preserve the Union. Therefore, at first, he would 

not permit African American volunteers from the North to enlist.

Developing a policy for dealing with escaping slaves was even more 

confusing. At first, some were put to work for the Union forces, while 

others were returned to their owners. Then, in August of 1861, fugitive 

slaves were declared to be “contraband of war” if their labor had been 

used to aid the Confederacy. If found to be contraband, the former 

slaves became confiscated property of the Union, but in essence, they 

were really freed. 

Slaves from the South fled to Union lines and some took refuge in 

newly forming contraband camps. In some of these camps, formerly 

enslaved people gained their first taste of freedom and an opportunity 

for education. Some built their own communities with telling names 

such as Promiseland and Fredonia.

By 1862, Lincoln was considering emancipating slaves under 

Confederate control as a military strategy to win the war. 

The South had been using slaves to aid the war effort. Black 

men and women had been forced to build fortifications, 

work as blacksmiths, nurses, and laundresses, and to work 

in factories and armories. Meanwhile, the North was 

refusing to accept the services of black volunteers and 

freed slaves—the people who most wanted to defeat 

the slaveholders. However, after Lincoln issued the

Emancipation Proclamation, the Union army 

accepted black soldiers into its ranks. 

Statue of a teacher helping her young 

student to read at the Contraband 

Camp in Corinth, Mississippi.

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NPS/SHILOH NMP

President Lincoln 

issues the Emancipation 

Proclamation, freeing 

the slaves under 

Confederate control.

Fire must be met with 

water, darkness with 

light, and war for the 

destruction of liberty, 

must be met with war 

for the destruction 

of slavery. The simple 

way, then, to put an end 

to the savage and 

desolating war now 

waged by slaveholders, is 

to strike down slavery 

itself, the primal cause 

of that war.” 

 

Frederick Douglass, 

Abolitionist

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African American men rushed to enlist. Contraband and 

Colored Troops served in all-black units commanded by white 

officers. Though they faced segregation and discrimination, they 

fought with valor, their contributions helping turn the tide of 

battles. By the end of the war, roughly 180,000 troops were men 

of color, some earning the highest military honors. 

When the charge 

was started, our 

Color guard was full; 

two sergeants and 

ten corporals. Only 

one of the twelve 

came off that field on 

his own feet. Most of 

them are there still

...It was a deadly 

hailstorm of bullets 

sweeping men down 

as hail-stones sweep 

the leaves from trees... 

Sgt. Major Christian 

Fleetwood, USCT, 

Medal of Honor 

Recipient

NPS/FORT SUMTER NM

U.S. Colored Troops, 

54th Massachusetts, 

Reenactors

LIBRARY OF CONGRESS

NPS/KENNESAW MOUNTAIN NBP

At the Battle of 

Chaffin’s Farm, with 

most of the officers dead 

or wounded, the sergeants 

of the 4th United States 

Colored Troops (USCT) 

assumed leadership. 

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Historians have said the Civil War was the 

unfinished business of the Revolution and 

the Constitution, and yet today that business 

is still incomplete. There are still obstacles to 

overcome before Americans of every creed, 

color, and gender are truly equal. If the 

Civil War was the defining moment in the 

history of the nation 150 years ago, this then, 

is the defining task of the current generation.

To what end did 620,000 

soldiers sacrifice their lives? 

In the end, the Civil War 

determined what type of a country 

we would be—united; 

and what type of a people 

we would be—free.

Unfinished Business

ANDERSONVILLE NHS

U.S. Department of the Interior

National Park Service

Southeast Region