Rereading the American Civil War: A War That Was Never Inevitable

The American Civil War was one of the deadliest civil wars in human history, claiming over 700,000 lives and making it the bloodiest conflict in American history relative to the nation's population. Renowned Civil War historian Gary Gallagher offered a deeply insightful and convention-challenging analysis of the war's causes, course, and legacy on the Lex Fridman podcast. Drawing from that conversation, this article distills the most illuminating historical insights.

The Root Cause of the War: Slavery Is the Only Answer

On the question of what caused the Civil War, Gallagher offers an unequivocal judgment: "If you take slavery out of the picture, there is no Civil War. It's that simple." This is a core argument that bears repeating—because it is so often blurred, whether intentionally or not.

Yet the complexity of history lies in the fact that the debate before the war was not about "abolishing slavery" per se, but about whether slavery could expand into new federal territories. The core platform of the Republican Party in 1860 was not abolition, but rather "no expansion of slavery into new territories." For white Southerners, this meant they would inevitably become an increasingly marginalized minority within the nation, and that a federal government dominated by free states would sooner or later cross a line they could not tolerate—threatening the institution of slavery in the South itself.

This debate was rooted in a series of constitutional compromises dating back to the nation's founding. The Northwest Ordinance of 1787 prohibited slavery north of the Ohio River; the Missouri Compromise of 1820 drew a line at 36°30' north latitude to delineate the spheres of free and slave states; and the Kansas-Nebraska Act of 1854 upended that balance by introducing the principle of "popular sovereignty," allowing settlers in new territories to decide for themselves whether to permit slavery. These successive shifts turned every new piece of territory into a wager on the Union's survival, as the balance of free-state and slave-state seats in the Senate directly determined the direction of federal policy.

Interestingly, abolitionists were actually a tiny minority at the time. Even in the North, genuine abolitionists may have constituted only about 3% of the population. Abolitionism was far from monolithic—it encompassed a range of positions. Radical voices like William Lloyd Garrison demanded the immediate, unconditional abolition of slavery, going so far as to call the Constitution "a covenant with the devil." Others, like Frederick Douglass, believed emancipation could be achieved within the constitutional framework. Most Northerners held a "Free Soil" position—they opposed the expansion of slavery not out of concern for Black rights, but because they feared slave labor would undercut the economic opportunities of free white workers. This diversity of positions explains why "abolition" as a political platform lacked electoral appeal. And white attitudes toward Black people at the time were, in Gallagher's words, "universally marked by deep prejudice"—a prejudice just as deeply rooted in free states. Understanding this is essential to truly grasping the mental world of that era.

Causation vs. Motivation: Why a Vermont Farmer Would Die for the Union

Gallagher places special emphasis on a conceptual distinction that is often confused in historical analysis: causation and motivation are two different things.

Slavery was the cause of the war, but the vast majority of Northern soldiers who put on the blue uniform were not fighting to destroy slavery. So why would a farm boy from Vermont or Ohio risk death to bring South Carolina back into the Union?

Gallagher argues the key lies in the concept of "Union"—a word that has almost vanished from the American vocabulary today. For that generation, the Union was a unique gift purchased with the blood of the revolutionary founders: it meant citizens had a voice in their own government, and it meant economic upward mobility—"you didn't have to be what your father was."

For Americans in the mid-19th century, "Union" was not merely a political entity but a near-sacred idea. It embodied the political experiment of the Enlightenment—proving that people could govern themselves through reason and elections, without relying on monarchs or hereditary aristocrats. Against the backdrop of European nations still ruled by royal houses, America's republican experiment was seen as the litmus test for the cause of human freedom worldwide. Lincoln's words at Gettysburg—"that government of the people, by the people, for the people, shall not perish from the earth"—were the ultimate expression of this belief. If secession succeeded, it would prove to the world that republican government was inherently fragile and unsustainable. If a republic was too fragile to withstand the outcome of a single election, then the sacrifices of the founding generation would have been for nothing.

This is the essence of the "citizen soldier" ethos: you received these rights from the republic, and you have an obligation to give back. This idea traces back to the traditions of the Roman Republic, transmitted into Anglo-American thought through Machiavelli's political philosophy during the Renaissance. Its core logic is that standing armies threaten liberty, while citizens who engage in productive work during peacetime and take up arms to defend the republic in wartime are the hallmark of a healthy polity. America's founding generation was deeply influenced by this tradition, and the National Guard system and the Second Amendment are its institutional legacies. The mobilization of millions of volunteers during the Civil War was the largest-scale test of this ideal in practice.

Key Figures: The Decisive Role of Individuals in History

Gallagher is blunt about the historical view that "great impersonal forces determine everything and individuals are irrelevant"—he calls it "absurd."

"Individuals really matter. For the United States, the roles of Lincoln and Grant in this war are immeasurable. And on the Southern side, if you take Lee away, the war doesn't last nearly as long."

Lincoln is an enigma in Gallagher's eyes. A frontier lawyer with less than a year of formal education became the most eloquent president in American history, capable of distilling the most complex ideas into the most precise language. Even more remarkable was his willingness to bring his chief rivals into the cabinet, his ability to set aside ego and focus on objectives, his openness to listening to those who knew more than he did, and his capacity to admit mistakes and change course. His Second Inaugural Address is hailed by Gallagher as "the greatest speech in American history"—with victory in sight, Lincoln did not stoke vengeance but told his audience: slavery was the root cause of this war, and all of us were complicit in it.

Grant was a man who had failed repeatedly in farming, business, and peacetime military service, only to reveal military genius in war. He was willing to break rules, take risks, accept responsibility for outcomes, and refuse to be broken by setbacks. Grant's military talent lay in his intuitive understanding of the nature of modern warfare. He was among the first commanders to recognize that the Civil War had entered the era of "total war"—that victory depended not only on battlefield maneuver and decisive engagement, but on the systematic attrition of the enemy's logistics, economic base, and popular will. His bold maneuvering at Vicksburg—cutting his own supply lines and plunging deep behind enemy lines—defied the military textbooks of the day. As General-in-Chief, his coordinated strategy demanded simultaneous offensives across all Union theaters, denying the South the ability to shift forces along interior lines—a form of thinking that foreshadowed 20th-century grand strategy.

The data is deeply ironic: before the two men faced each other directly, Grant's total casualties across all major campaigns were 37,000, while Lee's stood at a staggering 98,000. By one estimate, the probability of becoming a casualty while serving in Lee's army was as high as 73%. The label of "butcher," it turns out, should rightly have belonged to Lee.

Lee was born into one of Virginia's most elite aristocratic families, idolized Washington, yet nearly destroyed what Washington had built. He chose Virginia—a choice bound up with his loyalty to family and to the slaveholding South. Lee's military talent is beyond question, but the casualty data Gallagher reveals points to a deeper paradox: Lee favored offensive campaigns, pursuing Napoleonic battles of annihilation—a strategy that, given the Confederacy's severe manpower disadvantage, actually accelerated the South's attrition. By contrast, General Joseph E. Johnston in the Confederate western theater advocated a defensive strategy, prolonging the war at lower cost and forcing Northern public opinion to turn against it. Lee's offensive inclination—from the Seven Days Battles to Gettysburg—often produced brilliant tactical victories but may have been the Confederacy's greatest act of self-harm at the strategic level. This analysis overturns the "Lost Cause" narrative that mythologized Lee as the perfect general.

A War That Was Never Inevitable: The Power of Historical Contingency

Gallagher's most controversial and most thought-provoking argument is his rejection of the idea that the Civil War was "inevitable." He calls the tendency to "read backward from the ending and assume everything had to happen" the "Appomattox syndrome."

History unfolds sequentially: Lincoln was elected, South Carolina seceded, other states followed… Each step was a consequence of the previous one, not a predetermined outcome. Had Lincoln decided to abandon Fort Sumter, the Upper South states—especially the critically important Virginia—might never have left the Union.

The Fort Sumter crisis of April 1861 was the first major test Lincoln faced after taking office. The federal fort in Charleston Harbor, South Carolina, was running low on supplies, and Lincoln faced a three-way choice: abandon the fort (effectively conceding the legitimacy of secession), reinforce it militarily (which could be seen as the North starting the war), or send only supplies rather than military reinforcements. Lincoln chose the third path—publicly announcing that only food would be sent, shifting the moral burden of firing the first shot onto the South. Jefferson Davis decided to bombard the fort before the supply ships arrived, thereby saddling the Confederacy with the image of the aggressor. This masterful political gambit directly forced the still-wavering Upper South states to choose sides.

Virginia's secession convention had twice voted against secession; only after Fort Sumter did it reverse course. And Virginia possessed 40% of the entire South's industrial capacity, its largest population, and its most important military leaders—without it, the Confederacy would have been an entirely different entity.

"The conditions were in place that made the war possible," Gallagher concludes, "but that doesn't mean it had to happen."

Military Balance and the True Turning Point of the War

Gallagher also corrects the myth that "the North was destined to win." While the North had a population of 22 million and overwhelming economic advantages, the Confederacy had compensating advantages: its threshold for victory was far lower—it didn't need to conquer the North, only to convince Northern citizens that "bringing these rebellious states back isn't worth the cost." Add to this the South's vast territory (roughly equivalent to all of Western Europe), its poor transportation infrastructure, and the psychological advantage of "fighting to defend the homeland." Gallagher draws a parallel to the Vietnam War: a side can be undefeated militarily, yet the collapse of public support can still end the war.

The true turning point was not the commonly cited Gettysburg. Gallagher argues that the fall of Atlanta in 1864 and Sheridan's victories in the Shenandoah Valley were the events that reignited Northern morale and made Lincoln's reelection possible. Before that, the summer of 1864 was the nadir of Northern public confidence—Lincoln himself believed at one point that he would not be reelected.

It was Sherman's "March to the Sea"—a strategy of destroying agricultural infrastructure and psychologically breaking the enemy—that ultimately shattered the Confederacy's backbone. Sherman's November 1864 march from Atlanta to Savannah was an early exemplar of total war in military history. He led 60,000 troops while cutting himself off from rear supply lines, living off the land and systematically destroying railroads, factories, cotton gins, and warehouses along the route—while deliberately avoiding mass civilian casualties. The strategic intent was twofold: materially dismantling the South's war economy, and psychologically demonstrating to Southern civilians that their government was powerless to protect them. This concept of "hard war"—targeting a society's capacity to sustain war rather than just its armies—foreshadowed the logic of strategic bombing in the two World Wars of the 20th century, though those campaigns were far more destructive than Sherman's.

The War's Legacy: The Long Distance Between Reunion and Reconciliation

The war ended slavery within four years; without it, the institution might have persisted for decades longer. In 1860, the property controlled by slaveholders—slaves alone—was valued at approximately $3 billion, exceeding the combined value of all American industry and railroads. To understand why slavery could never have "died a natural death," one must recognize its central role in the American economy of the 1860s. The market value of the South's roughly 4 million enslaved people was estimated at $3–4 billion, while the federal government's annual budget was only about $63 million. Cotton accounted for nearly 60% of total U.S. exports, supplying the textile mills of Lancashire, England, and the global garment industry. Slavery was deeply embedded in the international capitalist system: New York banks extended loans to Southern plantations, New England factories processed Southern cotton, and Liverpool merchants underwrote the cotton trade. It was a transatlantic economic ecosystem with powerful self-perpetuating momentum. Slavery was not "dying out"—it was thriving.

After the war, the generous terms Grant extended to Lee's army at Appomattox—issuing rations, allowing soldiers to keep their horses, no imprisonment or executions—reflected Lincoln's goal of "rebuilding the nation." The surrender terms signed by Grant and Lee at Appomattox Court House on April 9, 1865, were renowned for their magnanimity: Confederate soldiers could go home after signing a pledge not to take up arms again; officers could keep their sidearms and horses; enlisted men who owned horses could keep them for spring planting; and Grant ordered 25,000 rations distributed to the starving Southern troops. Gallagher contrasts this with the humiliating consequences of the Treaty of Versailles after World War I, highlighting the wisdom of avoiding long-term resentment.

But he also soberly points out: Reunion and Reconciliation are two different things—the former was achieved, the latter took far longer. After Lincoln's assassination, Reconstruction policy lurched violently between Radical Republicans and successor President Andrew Johnson. The Reconstruction era of 1865–1877 saw the passage of the Thirteenth, Fourteenth, and Fifteenth Amendments, briefly granting former slaves citizenship and voting rights. But after federal troops withdrew from the South in 1877, the Jim Crow legal system rapidly took hold, systematically stripping Black people of their political and social rights—a condition that would not begin to be reversed until the Civil Rights Movement nearly a century later.

As for the current discourse about a "new civil war," Gallagher—as a scholar who has spent his life studying the Civil War—does not believe America is on the brink of a split comparable to the 19th century. He acknowledges similarities between the present and the 1850s—people's tendency to attribute the worst motives to the other side, the prevalence of inflammatory rhetoric. But he emphasizes that today no congressman is being beaten on the floor of Congress, and while states may talk of secession, none has actually convened a secession convention or sent delegates.

He holds a genuine optimism about the resilience of this republic: "I've seen it go through much more difficult times than now, and it came through and kept going." The long arc of history bends toward the expansion of liberty and rights. And the foundation for all of this, Gallagher believes, traces back to the wisdom of that generation in Philadelphia in 1787—they created a document resilient enough and adaptable enough to allow the republic to confront a challenge as destructive as slavery.

History is complex precisely because human beings are part of it. And understanding that complexity—refusing the "30-second version" of a simple good-versus-evil narrative—may be the most profound lesson this conversation leaves us with.