Tensions in American society today have analysts hurriedly investigating the origins of America’s Civil War. Can they glean lessons from that tragic history? Numerous volumes have been written on the subject, but two new complementary contributions shed some additional light.

The American Civil War Museum’s acclaimed new exhibit, “The Impending Crisis: How Slavery Caused the Civil War,” focuses on slavery as the key underlying cause of the conflict. The exhibit begins with the declaration that slavery in the United States was unique because it was based entirely on race and not conquest or debt bondage, as in other slave societies. It was meant to be permanent, with bondage passed down through the generations. The exhibit notes that this notion was the foundation of the antebellum South’s economy and society. It was also the fault line upon which the Union collapsed. 

The second new source, Erik Larson’s brilliant book, The Demon of Unrest, complements the Museum’s exhibit by examining in detail both antebellum Southern culture and an almost daily account of the critical five months between Abraham Lincoln’s November 6, 1860 election and the April 12 firing on Fort Sumter. His reporting from the diary of South Carolina lady Mary Chestnut of the excitement and romance in Charleston leading up to the attack paints an insightful picture.

Combining the two contributions, we have identified ten factors that together created the conditions for war. These factors reveal the tensions resulting from two disparate sets of economies, interests, cultures, values, beliefs, and calculations. These factors overlapped with cascading effects, and events took their course. By April 1861, neither side could back away from war without fundamentally altering their basic beliefs and institutions.

Competing Methods of Wealth Creation

Slavery was not mentioned directly in the Constitution, though the three-fifths clause recognized its existence. Most Founding Fathers assumed that slavery would wither away as the practice became unprofitable and inefficient. This changed in 1793 when the cotton gin and new textile manufacturing techniques revitalized the plantation economy. In the North, the Industrial Revolution created wealth for manufacturers based on free labor. These divergent methods of wealth creation prompted differing lifestyles, economic realities, and cultures throughout the first half of the nineteenth century. The states that shared similar views were contiguous, creating potential for regional geographic division. 

The Museum’s exhibit explores the tensions that arose between the free labor movement and slavery. Free labor advocates identified with the democratic struggles against the thrones and altars of Europe. Horace Greeley, editor of the New York Tribune, praised the 1848 revolutions to amplify the opposition of free labor to the slave power in the United States. The exhibit presents a fascinating graph of how free labor, compared to enslavement, affected the development of society. In the North, public schools, libraries, newspapers and periodicals, population, cities, highways, canals, and railroads far outpaced the South. Northerners thought of the South as backward and undeveloped, even though its large enslaved population made a sliver of Southern society fabulously wealthy.

The exhibit features a photograph of the scandalous Congressman James Henry Hammond, who pronounced, “Cotton is king,” reinforcing the belief among Southern plantation owners that enslavement was essential to the financial well-being of the entire nation. This small group of wealthy planters became known as the “slave power” because of their extensive control of Southern society and their outsized influence over the Federal government.

Contradictory Values

Differing methods of wealth creation led to dramatic contradictions in values and codes of honor between the South and North. Larson quotes one of Hammond’s speeches on the floor of the House of Representatives, in which he declared of enslaved peoples that “As a class, I say it boldly, there is not a happier, more contented race upon the face of the earth.” This justification for keeping millions of people in bondage spread widely in the South during the next twenty-five years. “The Impending Crisis” also provides a helpful exposition of religious, scientific, and political defense of the “peculiar institution.” To white Southerners like Sarah B. Valentine, enslavement was ordained by God and endorsed in the Bible. White Southerners accepted pseudo-scientific theories that Africans were prone to violent and degenerate tendencies. 

These distorted values were amplified by the so-called Code Duello, which Larson quotes at length. This code was a guide for Southern “chivalry,” outlining how Southerners should protect their honor and righteousness. Larson implicitly compares the road to civil war with the path to a duel. The brutal 1856 “caning” by South Carolina representative Preston Brooks against Massachusetts senator Charles Sumner on the floor of the Senate was seen in the South as consistent with Southern chivalry.

The “Impending Crisis” also delves into the growth of the Abolitionist movement in the North, showing how opposition to enslavement grew as more slaves escaped and told their stories. The example of Frederick Douglas is highlighted. An astonishing map of the Underground Railroad shows how 40,000 escaped slaves made it to Canada, and another 5000 made it to Mexico. Freeborn blacks are shown to have had a significant influence on the Abolitionists. 

The passage of the 1850 Fugitive Slave Act, intended to placate Southern slaveowners, had the effect of further stimulating the Abolitionist movement. The North grew ever more militant, sparked by Harriet Beecher Stowe’s 1852 classic novel Uncle Tom’s Cabin. Stowe’s main character, the “God-fearing Tom,” is acquired by the wicked plantation owner Simon Legree, who separates families, abuses female slaves, and finally has kind old Tom whipped to death. 

As these two diametrically opposed images of enslavement took hold, room for moral compromise diminished. These contradictions led to what Larson called “extreme rhetorical combat” in Congress. Actions taken in the North to counter what many saw as a “fundamental evil” became an affront to Southern honor.

Contending Appraisals of Secession

The Constitution did not explicitly provide the states with recourse to secession from the Union. Nonetheless, the question was frequently raised throughout the early republic—and not always in the South. The issue came to the fore in the 1790s with the Whiskey Rebellion and the Virginia and Kentucky Resolutions. Aaron Burr’s conspiracy to form a confederation of western states, the 1814 Hartford Convention, and the 1832–33 Nullification Crisis kept the question alive in the early nineteenth century. However, secessionists were kept in check by a combination of strong federal leadership and Congress’ willingness to compromise. During the Whiskey Rebellion, George Washington led federal forces against Pennsylvania’s tax revolt. During the Nullification Crisis, Andrew Jackson threatened to lead an army against South Carolina. Every early consideration of secession failed to gain traction and threaten the federal government. 

By 1860, things had changed. Larson notes that South Carolina’s declaration of secession inaccurately quoted Thomas Jefferson’s words in the Declaration of Independence that “whenever any form of government becomes destructive…it is the right of the people to abolish it.” Jefferson Davis, to his dying day, argued that the South had a constitutional right to secede. In the North, the Declaration’s promise that “all men are created equal” dominated. Lincoln held that the Union was sacrosanct and that it was his constitutional duty to assure that “government of the people, by the people and for the people, shall not perish from the earth.” This contradiction gave rise to the Lost Cause argument that the origin of the Civil War lay in the debate over the right of state governments to secede, ignoring the fact that the sole reason for seceding was to preserve slavery.

The High Stakes of Westward Expansion

American expansion westward created additional tensions for the divided nation. At stake was both how far slavery would spill over into the new territories and how the balance of power in Washington would be impacted once the territories became states. Politicians like Henry Clay and Daniel Webster sought to diffuse tensions through compromise legislation. The 1820 Missouri Compromise admitted Maine as a free state and Missouri as a slave state. The Compromise of 1850 admitted California as a free state and adjusted the borders of the newly admitted slave state, Texas, consistent with the Missouri Compromise. 

Efforts to maintain this geographic balance withered as Kansas and Nebraska sought statehood. As “The Impending Crisis” demonstrates, the 1854 Kansas-Nebraska Act, which allowed enslavement to expand to new territories if approved by the local population (thereby nullifying the 1820 Missouri Compromise), appeased the slave power somewhat, enraged the Northern opposition, promoted open warfare in these two territories, and led to the Lincoln Douglas debates, which made Lincoln famous. In the 1857 Dred Scott v. Sandford decision, the Supreme Court further ruled that Congress did not have the power to ban slavery in any territory. 

The shift from compromise to confrontation over slavery in the territories further divided the nation. Lincoln opposed the expansion of slavery to new territories, and Southerners felt that a reversal of the Dred Scott decision would eventually shift the balance of power against them in Congress. 

Southern Fears of Extinction

Southerners calculated the threats to their well-being, weighing the risk of a slave uprising triggered by abolition with the apparently less risky prospect of a war for secession. Ultimately, they got it wrong.