African-American slavery existed in the United States almost since the first European colonists arrived in the New World. By the outbreak of the Civil War there were four million slaves in the Southern states while the institution had been abolished in Northern states shortly after the turn of the century. Historian George M. Fredrickson—and many other Americans—have called slavery "America's original sin."

Two Issues of Slavery: Morality and States' Rights

There were always two major issues with the institution of slavery in the United States. The first one, as implied by Fredrickson, is moral. The second one involves states' rights. Click on the pictures below to learn more about each.

→ Reflection: Examine the quote by Abraham Lincoln and the two pictures above. Can someone combine the morality and states' rights issues?

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Yes and Lincoln certainly did. If slavery is as profoundly wrong as the pictures help illustrate, then no state has a right to do it. Lincoln points out that slaves have no right of self-government; they are under a despotism, or a government with absolute power.

Ongoing Conflict

These issues created tension throughout U.S. history as Southern states fiercely defended their right to own slaves. Click on the timeline below to review a few key moments of conflict from U.S. history prior to the Civil War.

→ Reflection: In all of the above disagreements, how did the North and South remain unified?

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In all of these circumstances, the North and South either reached a deal or compromised, or the pro-slavery individuals were accommodated such as in the gag rule.

Build Up to the Civil War

For the most part, feelings of nationalism and the willingness to compromise kept the nation together. Yet, neither the issue of morality or states' rights would go away. In fact, by the time of the Civil War, the two sections of the country had become even more different. Eventually, the two sides simply found it impossible to compromise and the South would try to assert its right to leave the Union.