Critics of the movement to remove Confederate monuments often come back to the question: where will it end? As President Trump asked, if we take down statues of Robert E. Lee and Jefferson Davis, will we then have to take down statues of George Washington and Thomas Jefferson, too?

Supporters of monument removal have not always been persuasive when responding to this slippery-slope argument. They are wary of admitting that it will be difficult to reject the Lost Cause — the collection of historical myths meant to whitewash the hard truths of slavery and the Civil War — without rejecting American nationalism.

And they’re right to be wary because the Lost Cause was itself a project of American nationalism. Many Americans felt it was necessary to adopt the myths of the Lost Cause to heal the wounds of the Civil War and rebuild the nation — even if this meant leaving African Americans behind. American nationalism and the Lost Cause are therefore tightly woven together, and unweaving them will require careful attention and honest conversation. Those who want to remove Lost Cause iconography from the public square must do the hard work of that unweaving or else the slippery-slope argument will be nearly insurmountable.

Those who wish to separate the Founders from the Confederates point out that while Washington and Jefferson owned slaves, they also did much good, and their monuments commemorate the good they did, not the evils they failed to overcome. Indeed, the principles of democracy and equality they espoused later emboldened the abolitionist movement and ultimately doomed the institution of slavery.

This argument is undermined, however, by the presence of more radical voices, particularly black voices, who reject it as slavery apologetics. We cannot, they argue, set apart some people as “good” slaveholders and others as “bad” slaveholders, or else we obscure the evil of slaveholding itself. Broderick Greer, an Episcopal priest in Memphis, has said plainly: “Enslavers don’t deserve public reverence.” Al Sharpton has even called for the public defunding of the Jefferson Memorial.

Others adopt a different tactic: emphasizing that the Confederates were traitors. Davis and Lee, both U.S. Military Academy grads, betrayed their oaths to “defend the Constitution of the United States.” Though many of the Founders owned slaves, and many other American heroes were white supremacists, at least they did not betray their country.

But the traitor argument assumes an understanding of loyalty and nationality that historians are usually uncomfortable with, one that takes only the view of the victors into account. From the British point of view, what Washington and Jefferson did in leading the American Revolution was nothing short of treason. From the Confederates’ point of view, meanwhile, seceding from the United States was their way of staying true to the Founders’ vision of American liberty.

That sense of continuity with the Founders was an essential part of the Confederate argument. A delegate at the Confederate Constitutional Convention proposed they name their new nation the Republic of Washington. Davis was inaugurated on Washington’s birthday and proclaimed that the Confederacy would “perpetuate the principles of our Revolutionary fathers.”  According to secessionists, the Founders, whatever their reservations, had left slavery intact, and it was Lincoln’s Republican Party that had violated this agreement and betrayed the Constitution.

And the Confederates had good reason to believe this rationale. The United States had not only been a slaveholding nation for nearly a century. It also presided over the forceful removal of Native Americans. This deep vein of American racism continued after the Civil War with the mass murder of Filipino insurrectionaries and the internment of Americans of Japanese descent. Both Confederate nationalism and American nationalism centered on a celebration of white supremacy.

In fact, this shared commitment to white supremacy made reunion possible after the Civil War, at the expense of justice for African Americans. Many Americans believed it was necessary for the health of the nation to let bygones be bygones and reintegrate white southerners into the body politic. For white northerners, this meant abandoning Reconstruction — the period when the federal government intervened to protect freed people’s lives and rights — and ceding the “Negro question” to white southerners, who quickly erected a system of segregation backed by anti-black terrorism.

It also meant rewriting history. In this new version, slavery was benign instead of cruel, and the Confederates seceded to preserve states’ rights rather than slavery. (Few thought to ask why the second assertion was necessary if the first was true.) Like slavery and the war, Reconstruction too was whitewashed. At the war’s end, white northerners initially saw “carpetbaggers” — northern migrants to the South — as heroic crusaders who would transform the South into a land of free labor and free soil. Within a decade, however, they turned against the carpetbaggers, recasting them as invaders who only wished to fleece the South and provoke the black population into a potential race war.

A reunification of the nation that failed to fully address the legacies of slavery was only justifiable if the war had not been about slavery. Instead, the war became God’s way of strengthening the nation. Thomas F. Gailor, the Episcopal bishop of Tennessee at the turn of the 20th century, claimed that before the Civil War, Americans said that the United States “are”; after the war, they said “the United States is.” The persistence of this narrative can be seen in Ken Burns’s 1990 documentary “The Civil War,” in which the novelist Shelby Foote, with his mesmerizing Mississippi drawl, repeated Gailor’s claim about “is” and “are.” Burns echoed this story in several interviews and considered it the essence of his documentary’s story.

In this imagining of the war, it mattered little what either side had fought for. What mattered was that they had fought, and that out of the bloodshed emerged a new nation. It was in this vein that Americans celebrated the service of white southern men, including a former Confederate general, in the Spanish-American War, when the United States became a traditional imperial power.

It was also in this vein that D.W. Griffith titled his white-supremacist propaganda film about the Civil War and Reconstruction, “The Birth of a Nation,” which audiences in the North and the South made the first American blockbuster. And it was in this vein that Trump implied that Lee was a Founding Father — a man who helped shed the blood that gave birth to a stronger nation.

Perhaps the United States did not need to abandon the cause of emancipation and adopt the Lost Cause myth to reintegrate the South. Perhaps it did not need to choose reunion of white Americans over justice for black Americans to get past the war and become the greatest economic and imperial force in the world. But we’ll never know, because that’s what it did. This is why those who want to take down Confederate monuments have a hard time reconciling it with their dedication to American nationalism. This is why they are not sure whether to declare, “This is not us!,” in the wake of white-supremacist violence, or to say, sadly, “This is us.”

They are afraid of where this kind of talk might end.