Across the map of the United States, the borders of Tennessee, Oklahoma, New Mexico, and Arizona draw a distinct line. It's the 36º30′ line, a remnant of the boundary between free and slave states drawn in 1820. It is a scar across the belly of America, and a vivid symbol of the ways in which slavery still touches nearly every facet of American history.

That pervasive legacy is the subject of a series of articles in The New York Times titled "The 1619 Project." To cover the history of slavery and its modern effects is certainly a worthy goal, and much of the Project achieves that goal effectively. Khalil Gibran Muhammad's portrait of the Louisiana sugar industry, for instance, vividly covers a region that its victims considered the worst of all of slavery's forms. Even better is Nikole Hannah-Jones's celebration of black-led political movements. She is certainly correct that "without the idealistic, strenuous and patriotic efforts of black Americans, our democracy today would most likely look very different" and "might not be a democracy at all."

Where the 1619 articles go wrong is in a persistent and off-key theme: an effort to prove that slavery "is the country's very origin," that slavery is the source of "nearly everything that has truly made America exceptional," and that, in Hannah-Jones's words, the founders "used" "racist ideology" "at the nation's founding." In this, the Times steps beyond history and into political polemic—one based on a falsehood and that in an essential way, repudiates the work of countless people of all races, including those Hannah-Jones celebrates, who have believed that what makes America "exceptional" is the proposition that all men are created equal.

For one thing, the idea that, in Hannah-Jones' words, the "white men" who wrote the Declaration of Independence "did not believe" its words applied to black people is simply false. John Adams, James Madison, George Washington, Thomas Jefferson, and others said at the time that the doctrine of equality rendered slavery anathema. True, Jefferson also wrote the infamous passages suggesting that "the blacks…are inferior to the whites in the endowments both of body and mind," but he thought even that was irrelevant to the question of slavery's immorality. "Whatever be their degree of talent," Jefferson wrote, "it is no measure of their rights. Because Sir Isaac Newton was superior to others in understanding, he was not therefore lord of the person or property of others."

The myth that America was premised on slavery took off in the 1830s, not the 1770s. That was when John C. Calhoun, Alexander Stephens, George Fitzhugh, and others offered a new vision of America—one that either disregarded the facts of history to portray the founders as white supremacists, or denounced them for not being so. Relatively moderate figures such as Illinois Sen. Stephen Douglas twisted the language of the Declaration to say that the phrase "all men are created equal" actually meant only white men. Abraham Lincoln effectively refuted that in his debates with Douglas. Calhoun was, in a sense, more honest about his abhorrent views; he scorned the Declaration precisely because it made no color distinctions. "There is not a word of truth in it," wrote Calhoun. People are "in no sense…either free or equal." Indiana Sen. John Pettit was even more succinct. The Declaration, he said, was "a self-evident lie."

It was these men—the generation after the founding—who manufactured the myth of American white supremacy. They did so against the opposition of such figures as Lincoln, Charles Sumner, Frederick Douglass, and John Quincy Adams. "From the day of the declaration of independence," wrote Adams, the "wise rulers of the land" had counseled "to repair the injustice" of slavery, not perpetuate it. "Universal emancipation was the lesson which they had urged upon their contemporaries, and held forth as transcendent and irremissible [sic] duties to their children of the present age." These opponents of the new white supremacist myth were hardly fringe figures. Lincoln and Douglass were national leaders backed by millions who agreed with their opposition to the white supremacist lie. Adams was a former president. Sumner was nearly assassinated in the Senate for opposing white supremacy. Yet their work is never discussed in the Times articles.

In 1857, Chief Justice Roger Taney sought to make the myth into the law of the land by asserting in Scott v. Sandford that the United States was created as, and could only ever be, a nation for whites. "The right of property in a slave," he declared, "is distinctly and expressly affirmed in the Constitution." This was false: the Constitution contains no legal protection for slavery, and doesn't even use the word. Both Lincoln and Douglass answered Taney by citing the historical record as well as the text of the laws: the founders had called slavery both evil and inconsistent with their principles; they forbade the slave trade and tried to ban it in the territories; nothing in the Declaration or the Constitution established a color line; in fact, when the Constitution was ratified, black Americans were citizens in several states and could even vote. The founders deserved blame for not doing more, but the idea that they were white supremacists, said Douglass, was "a slander upon their memory."

Lincoln provided the most thorough refutation. There was only one piece of evidence, he observed, ever offered to support the thesis that the Declaration's authors didn't mean "all men" when they wrote it: that was the fact that they did not free the slaves on July 4, 1776. Yet there were many other explanations for that which did not prove the Declaration was a lie. Most obviously, some founders may simply have been hypocrites. But that individual failing did not prove that the Declaration excluded non-whites, or that the Constitution guaranteed slavery.

Even some abolitionists embraced the white supremacy legend. William Lloyd Garrison denounced the Constitution because he believed it protected slavery. This, Douglass replied, was false both legally and factually: those who claimed it was pro-slavery had the burden of proof—yet they never offered any. The Constitution's wording gave it no guarantees and provided plentiful means for abolishing it. In fact, none of its words would have to be changed for Congress to eliminate slavery overnight. It was slavery's defenders, he argued, not its enemies, who should fear the Constitution—and secession proved him right. Slaveocrats had realized that the Constitution was, in Douglass's words, "a glorious liberty document," and they wanted out.

Still, after the war, "Lost Cause" historians rehabilitated the Confederate vision, claiming the Constitution was a racist document, so that the legend remains today. The United States, writes Hannah-Jones, "was founded…as a slavocracy," and the Constitution "preserved and protected slavery." This is once more asserted as an uncontroverted fact—and Lincoln's and Douglass's refutations of it go unmentioned in the Times.

No doubt Taney would be delighted at this acceptance of his thesis. What accounts for it? The myth of a white supremacist founding has always served the emotional needs of many people. For racists, it offers a rationalization for hatred. For others, it offers a vision of the founders as arch-villains. Some find it comforting to believe that an evil as colossal as slavery could only be manufactured by diabolically perfect men rather than by quotidian politics and the banality of evil. For still others, it provides a new fable of the fall from Eden, attractive because it implies the possibility of a single act of redemption. If evil entered the world at a single time, by a conscious act, maybe it could be reversed by one conscious revolution.

The reality is more complex, more dreadful, and, in some ways, more glorious. After all, slavery was abolished, segregation was overturned, and the struggle today is carried on by people ultimately driven by their commitment to the principle that all men are created equal—the principle articulated at the nation's birth. It was precisely because millions of Americans have never bought the notion that America was built as a slavocracy—and have had historical grounds for that denial—that they were willing to lay their lives on the line, not only in the 1860s but ever since, to make good on the promissory note of the Declaration.

Their efforts raise the question of what counts as the historical "truth" about the American Dream. A nation's history, after all, occupies a realm between fact and moral commitments. Like a marriage, a constitution, or an ethical concept like "blame," it encompasses both what actually happened and the philosophical question of what those happenings mean. Slavery certainly happened—but so, too, did the abolitionist movement and the ratification of the Thirteenth, Fourteenth, and Fifteenth Amendments. The authors of those amendments viewed them not as changing the Constitution, but as rescuing it from Taney and other mythmakers who had tried to pervert it into a white supremacist document.

In fact, it would be more accurate to say that what makes America unique isn't slavery but the effort to abolish it. Slavery is among the oldest and most ubiquitous of all human institutions; as the Times series' title indicates, American slavery predated the American Revolution by a century and a half. What's unique about America is that it alone announced at birth the principle that all men are created equal—and that its people have struggled to realize that principle since then. As a result of their efforts, the Constitution today has much more to do with what happened in 1865 than in 1776, let alone 1619. Nothing could be more worthwhile than learning slavery's history, and remembering its victims and vanquishers. But to claim that America's essence is white supremacy is to swallow slavery's fatal lie.

As usual, Lincoln said it best. When the founders wrote of equality, he explained, they knew they had "no power to confer such a boon" at that instant. But that was not their purpose. Instead, they "set up a standard maxim for free society, which should be familiar to all, and revered by all; constantly looked to, constantly labored for, and even though never perfectly attained, constantly approximated, and thereby constantly spreading and deepening its influence, and augmenting the happiness and value of life to all people of all colors everywhere." That constant labor, in the generations that followed, is the true source of "nearly everything that has truly made America exceptional."