Merely asking this question says a lot about the average American’s knowledge of history. The “peculiar institution” was contentious when we were still colonies and part of William Wilberforce’s twenty-year campaign to end England’s international slave trade. After Parliament passed the Slave Trade Act of 1807, President Thomas Jefferson followed suit the following year.

Because slavery was such a controversial topic, the Founders judiciously avoided the word “slavery” in the Constitution. However, slaves were counted as three-fifths of a person for purposes of representation and taxation, enhancing the South’s power in national affairs, an advantage the South was determined to maintain. Thus, Article 1, Section 2 of the Constitution reads:

“Representatives and direct Taxes shall be apportioned among the several States … which shall be determined by … the … Number of free Persons, including those bound to Service for a term of years, and excluding Indians not taxed, three-fifths of all other Persons.” (emphasis added) The Constitution directly contradicted Southern Black Codes, which dehumanized blacks and treated them as mere property (chattel).

Virginia governor Thomas Jefferson and our third president was heavily conflicted over slavery. In his Notes on the State of Virginia (1785), Jefferson expressed his conviction that the practice corrupted both master and slave: “The whole commerce between master and slave is a perpetual exercise of the most boisterous passions, the most unremitting despotism on the one part, and degrading submission on the other… (Can) the liberties of a nation be thought more secure when we have removed their only firm basis, a conviction in the minds of the people that these liberties are the gift of God? That they are not to be violated but with his wrath? Indeed, I tremble for my country when I reflect that God is just; that His justice cannot sleep forever.” (emphasis added)

Jefferson feared that emancipating slaves on American soil would result in large-scale race war as brutal and deadly as the revolution that broke out in Haiti. He also believed that to keep slaves in bondage, with part of America in favor of abolition and part of America in favor of perpetuating slavery, might result in a civil war that would destroy the union. He noted in his Autobiography, written in 1821: “…it was found that the public mind would not bear… (gradual emancipation), nor will it bear it even at this day. Yet the day is not far distant when it must bear it, or worse will follow. Nothing is more certainly written in the book of fate that that these people are to be free.”

At the outbreak of the Civil War, there were about four and a half million blacks living in the United States; according to the 1860 census, 3,953,760 were slaves living in the South. The remainder, nearly half a million freemen, were evenly divided between the North and South, where they experienced extreme prejudice.

Our first big struggle over slavery was the Missouri Compromise of 1820. In the 1840s, the Mexican war was fought principally to insure the expansion of slavery, and met a mostly a cool reception in the North. Efforts were made to control slavery’s spread by the Wilmot Proviso, which would have banned slavery in territory acquired from Mexico. The Senate’s “gag rule” was imposed because of slavery, and the struggle over the spread of the institution into the Nebraska-Kansas territory resulted in the Compromise of 1850. In 1856, a Congressman from South Carolina caned Massachusetts Senator Charles Sumner over remarks made against slavery from the floor of Congress so savagely that he was unable to return to the Senate for nearly four years.

The South limited freedom of speech, press, and respect for free traffic in the Post Office, abridging the First Amendment and the Bill of Rights, to protect slavery. States from the “Deep South” — Alabama, Georgia, Louisiana, Mississippi and South Carolina sent fifty-two representatives to spread the “gospel of disunion” throughout the South. They insisted that “Black Republicans” threatened the institution of slavery and white supremacy by intimating that all humans were equal, including blacks. John Brown’s assault at Harpers Ferry in 1859, attempting to spark a slave revolt, sent the South into a frenzy of military preparation, and become the proximate cause of war.

Before the war, Senator Jeff Davis threatened secession on several occasions if Northern threats to slavery continued. Four of the five Articles of Secession issued by the eleven states which seceded established slavery as the reason for leaving the Union. The Confederacy’s vice president, Alexander Stevens, in his “Cornerstone” speech of March 21, 1861 explicitly identified the reason the South broke away:

“The new (Confederate} government 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 …had anticipated this as the “rock upon which the old Union would split.” (emphasis added)

I’m looking forward to comments arguing that the Civil War was over “States’ Rights” or tariffs. Please provide data and analysis!

Only an immense economic issue could have provoked such a cataclysmic and lengthy struggle…