Recent coverage of Syria’s civil war, now in its sixth year, has caused an uproar on cable news and social media platforms. In particular, images of the humanitarian fallout in Aleppo disturb American sensibilities. Aleppo was the besieged stronghold of American-backed rebel forces who oppose dictator Bashar al-Assad’s Putin-backed regime, and the scenes from there have been chilling: bleeding children, covered in dust, crying, or worse, shell-shocked and silent. Homes destroyed. Buildings hollowed out by relentless bombing. Roads cratered, hospitals and police stations left in ruin. Thousands of civilians caught in the crossfire, praying they will live to become refugees from the world’s most ancient city, while insurgents cling bitterly to whatever territory they can possess.

American responses have ranged from calls for direct military intervention, to increased humanitarian efforts, to plans for harboring Syrian refugees in the United States, to viewing the conflict as none of our business. What commentators seem to have in common, though, is the notion that this sort of violence—with its hollowed buildings, insurgents fighting from street to street, scorched earth policies, and ever-growing refugee rosters—is distinctly foreign; that is to say, it is not in keeping with how we fight our wars. It just isn’t American. Nothing along these lines ever has happened, or could now happen, within the civilized bounds of the United States.

In fact, we have indeed been in the very place Aleppo is now. Scenes like those seen lately taking place in the streets of that city played out on American soil during our own civil war.

By late summer 1863, the United States and the Confederate States of America had been engulfed in a bloody civil war to determine the fate of the Union and of slavery for more than two years. Massive armies, supplied by their respective governments, drilled in Napoleonic tactics, and bound for the most part by the established rules of war, had collided with dreadful impact at places like Manassas, Antietam, Fredericksburg, Chancellorsville, and Gettysburg. The casualties suffered by both armies were unprecedented in American history. But along the Missouri-Kansas Border, a region that was Union territory by definition for the entirety of the war, a different sort of conflict raged.

Here pro-Confederate bushwhackers squared off against various Union forces in a hyper-violent, hyper-localized struggle. The back roads, fields, barns, corncribs, and front porches of the homefront replaced traditional battlefields and war departments. Men, women, and children were all drawn into a conflict centered on households, the logistical nerve centers that made waging irregular war possible. To be a bystander in this conflict was impossible as ambuscade, arson, rape, torture, assassination, and massacre replaced uniforms, interior lines, and echelon formations. The established rules of war mattered very little. Guerrilla warfare constituted the status quo.

On August 21, 1863, this domestic strife reached its apogee. That morning, William Clarke Quantrill led several hundred Missouri bushwhackers in a dawn raid against Lawrence, Kansas. Quantrill’s men struck Lawrence—famed as the abolitionist stronghold of the West—without warning; they overran the town, shooting and burning. Within hours, they had killed nearly 200 men and boys, some cut down in their doorways, others dragged into the street and shot before horrified wives and children; still more were burned alive trying to hide from the guerrillas in cellars and attics. Blocks of town were torched. Around 180 buildings were lost, the damage reaching millions of dollars.

Even in the midst of a war claiming hundreds of thousands of lives, both the Union and the Confederacy recoiled from the Lawrence Massacre. Union General Thomas Ewing, Jr., in charge of the District of the Border in 1863, responded by issuing General Order #11; it forced rural residents in four Missouri counties—Jackson, Cass, Bates, and Vernon—either to prove their loyalty to the United States or be forcibly evacuated. Ewing and other Union officials had long understood that residents of these counties provided the logistics for guerrilla war: food, weapons, supplies, and intelligence. Their exile was a major blow for Quantrill and his ilk.

As Order #11 took effect, Union soldiers went door to door, issuing evacuation orders and threatening violence against those who might disobey them. Women packed up their children and what few belongings they could carry and left. A lucky minority had somewhere to go. Most simply started walking. The roads swelled with refugees in various states of desperation, walking past the lone chimneys that dotted the landscape where houses had once stood, burned out reminders of life before guerrilla war.

Americans have sanitized this dark page of our national bloodletting. Beginning with the war generation itself, the first architects of mainstream Civil War history pushed a narrative of mutual valor and shared honor. The story they worked to establish in publications like the Southern Historical Society Papers and Battles and Leaders of the Civil War touted the chivalry and courage of men from the ranks of both armies. This was not accidental. They sought to put the war behind them quickly to expedite the painful process of reunion. Nor was it an accident that they increasingly downplayed slavery, the root cause of the war. They began to argue that Confederate soldiers had fought for hearth and home, for honor, for their states, as their counterparts had fought for the Union.

Western guerrilla warfare destroyed the boundary that traditionally separated battlefront from homefront. Women, children, and the elderly weren’t forced to witness irregular violence in the guerrilla theater against their will, for survival they frequently took an active role. Women braining raiders with axes and men plundering homes under moonlit skies appeared anything but chivalrous or courageous to eastern eyes after the war. And the men who thrived on this sort of war—Quantrill, “Bloody Bill” Anderson, Cole Younger, Jesse and Frank James—didn’t look much like heroic veterans. Instead, they looked like savages who threatened to implode the whole idea of a civilized war fought between equally noble belligerents.

So Americans gradually read guerillas out of Civil War history and remade them into frontier cowboys, gunslingers, and Indian killers, men whose apparent lack of civility could be spun as a positive. The process began with outlaw histories published in the 1870s and 1880s, with titles like Train and Bank Robbers of the West (1882) and Outlaws of the Border (1882). It continued in dime novels such as Jesse James in Mexico; or, Raiders of the Rio Grande (1902) and Jesse James Surrounded; or, The Desperate Stand at Cutthroat Ranch (1903). Finally, motion pictures like Dark Command (1940), The Woman They Almost Lynched (1953), and The Outlaw Josey Wales (1976) completed the metamorphosis of the guerrilla killer into western hero.

For more than a century, commemorators of the Civil War depicted irregular warfare as a uniquely uncivilized endeavor. By categorizing western guerrillas as exceptionally awful, they could cleanse the regular war—their war—of some of its own viciousness.

And this brings us back to Aleppo, to the violence that seems foreign, to the warfare that could never happen in America. We deplore what has happened in Aleppo, but events there have not happened because the people in Syria are somehow different than us. This is not to simply say that all forms of war are uniformly terrible or without justification; rather, that there is no such thing as a truly “civilized” war. The fact that we have erased the memory of our own bloodstained guerrilla war is a reflection that we want to believe we would not conduct ourselves like “uncivilized people.” But during the American Civil War, we did.