George Packer is a staff writer for The Atlantic, where this article appears.

To assess the legacy of Donald Trump’s presidency, start by quantifying it. Since last February, more than a quarter of a million Americans have died from COVID-19—a fifth of the world’s deaths from the disease, the highest number of any country. In the three years before the pandemic, 2.3 million Americans lost their health insurance, accounting for up to 10,000 “excess deaths”; millions more lost coverage during the pandemic. The United States’ score on the human-rights organization Freedom House’s annual index dropped from 90 out of 100 under President Barack Obama to 86 under Trump, below that of Greece and Mauritius. Trump withdrew the U.S. from 13 international organizations, agreements, and treaties. The number of refugees admitted into the country annually fell from 85,000 to 12,000. About 400 miles of barrier were built along the southern border. The whereabouts of the parents of 666 children seized at the border by U.S. officials remain unknown.

America under Trump became less free, less equal, more divided, more alone, deeper in debt, swampier, dirtier, meaner, sicker, and deader. It also became more delusional. No number from Trump’s years in power will be more lastingly destructive than his 25,000 false or misleading statements. Super-spread by social media and cable news, they contaminated the minds of tens of millions of people. Trump’s lies will linger for years, poisoning the atmosphere like radioactive dust.

Presidents lie routinely, about everything from war to sex to their health. When the lies are consequential enough, they have a corrosive effect on democracy. Lyndon B. Johnson deceived Americans about the Gulf of Tonkin incident and everything else concerning the Vietnam War. Richard Nixon’s lifelong habit of prevaricating gave him the nickname “Tricky Dick.” After Vietnam and Watergate, Americans never fully recovered their trust in government. But these cases of presidential lying came from a time when the purpose was limited and rational: to cover up a scandal, make a disaster disappear, mislead the public in service of a particular goal. In a sense, Americans expected a degree of fabrication from their leaders. After Jimmy Carter, in his 1976 campaign, promised, “I’ll never lie to you,” and then pretty much kept his word, voters sent him back to Georgia. Ronald Reagan’s gauzy fictions were far more popular.

Trump’s lies were different. They belonged to the postmodern era. They were assaults against not this or that fact, but reality itself. They spread beyond public policy to invade private life, clouding the mental faculties of everyone who had to breathe his air, dissolving the very distinction between truth and falsehood. Their purpose was never the conventional desire to conceal something shameful from the public. He was stunningly forthright about things that other presidents would have gone to great lengths to keep secret: his true feelings about Senator John McCain and other war heroes; his eagerness to get rid of disloyal underlings; his desire for law enforcement to protect his friends and hurt his enemies; his effort to extort a foreign leader for dirt on a political adversary; his affection for Kim Jong Un and admiration for Vladimir Putin; his positive view of white nationalists; his hostility toward racial and religious minorities; and his contempt for women.

The most mendacious of Trump’s predecessors would have been careful to limit these thoughts to private recording systems. Trump spoke them openly, not because he couldn’t control his impulses, but intentionally, even systematically, in order to demolish the norms that would otherwise have constrained his power. To his supporters, his shamelessness became a badge of honesty and strength. They grasped the message that they, too, could say whatever they wanted without apology. To his opponents, fighting by the rules—even in as small a way as calling him “President Trump”—seemed like a sucker’s game. So the level of American political language was everywhere dragged down, leaving a gaping shame deficit.

Trump’s barrage of falsehoods—as many as 50 daily in the last fevered months of the 2020 campaign—complemented his unconcealed brutality. Lying was another variety of shamelessness. Just as he said aloud what he was supposed to keep to himself, he lied again and again about matters of settled fact—the more brazen and frequent the lie, the better. Two days after the polls closed, with the returns showing him almost certain to lose, Trump stood at the White House podium and declared himself the winner of an election that his opponent was trying to steal.

This crowning conspiracy theory of Trump’s presidency activated his entitled children, compliant staff, and sycophants in Congress and the media to issue dozens of statements declaring that the election was fraudulent. Following the mechanism of every big lie of the Trump years, the Republican Party establishment fell in line. Within a week of Election Day, false claims of voter fraud in swing states had received almost 5 million mentions in the press and on social media. In one poll, 70 percent of Republican voters concluded that the election hadn’t been free or fair.

So a stab-in-the-back narrative was buried in the minds of millions of Americans, where it burns away, as imperishable as a carbon isotope, consuming whatever is left of their trust in democratic institutions and values. This narrative will widen the gap between Trump believers and their compatriots who might live in the same town, but a different universe. And that was Trump’s purpose—to keep us locked in a mental prison where reality was unknowable so that he could go on wielding power, whether in or out of office, including the power to destroy.

For his opponents, the lies were intended to be profoundly demoralizing. Neither counting them nor checking facts nor debunking conspiracies made any difference. Trump demonstrated again and again that the truth doesn’t matter. In rational people this provoked incredulity, outrage, exhaustion, and finally an impulse to crawl away and abandon the field of politics to the fantasists.

For believers, the consequences were worse. They surrendered the ability to make basic judgments about facts, exiling themselves from the common framework of self-government. They became litter swirling in the wind of any preposterous claim that blew from @realDonaldTrump. Truth was whatever made the world whole again by hurting their enemies—the more far-fetched, the more potent and thrilling. After the election, as charges of voter fraud began to pile up, Matthew Sheffield, a reformed right-wing media activist, tweeted: “Truth for conservative journalists is anything that harms ‘the left.’ It doesn’t even have to be a fact. Trump’s numerous lies about any subject under the sun are thus justified because his deceptions point to a larger truth: that liberals are evil.”

How did half the country—practical, hands-on, self-reliant Americans, still balancing family budgets and following complex repair manuals—slip into such cognitive decline when it came to politics? Blaming ignorance or stupidity would be a mistake. You have to summon an act of will, a certain energy and imagination, to replace truth with the authority of a con man like Trump. Hannah Arendt, in The Origins of Totalitarianism, describes the susceptibility to propaganda of the atomized modern masses, “obsessed by a desire to escape from reality because in their essential homelessness they can no longer bear its accidental, incomprehensible aspects.” They seek refuge in “a man-made pattern of relative consistency” that bears little relation to reality. Though the U.S. is still a democratic republic, not a totalitarian regime, and Trump was an all-American demagogue, not a fascist dictator, his followers abandoned common sense and found their guide to the world in him. Defeat won’t change that.

Trump damaged the rest of us, too. He got as far as he did by appealing to the perennial hostility of popular masses toward elites. In a democracy, who gets to say what is true—the experts or the people? The historian Sophia Rosenfeld, author of Democracy and Truth, traces this conflict back to the Enlightenment, when modern democracy overthrew the authority of kings and priests: “The ideal of the democratic truth process has been threatened repeatedly ever since the late eighteenth century by the efforts of one or the other of these epistemic cohorts, expert or popular, to monopolize it.”

Monopoly of public policy by experts—trade negotiators, government bureaucrats, think tankers, professors, journalists—helped create the populist backlash that empowered Trump. His reign of lies drove educated Americans to place their faith, and even their identity, all the more certainly in experts, who didn’t always deserve it (the Centers for Disease Control and Prevention, election pollsters). The war between populists and experts relieved both sides of the democratic imperative to persuade. The standoff turned them into caricatures.

Trump’s legacy includes an extremist Republican Party that tries to hold on to power by flagrantly undemocratic means, and an opposition pushed toward its own version of extremism. He leaves behind a society in which the bonds of trust are degraded, in which his example licenses everyone to cheat on taxes and mock affliction. Many of his policies can be reversed or mitigated. It will be much harder to clear our minds of his lies and restore the shared understanding of reality—the agreement, however inconvenient, that A is A and not B—on which a democracy depends.

But we now have the chance, because two events in Trump’s last year in office broke the spell of his sinister perversion of the truth. The first was the coronavirus. The beginning of the end of Trump’s presidency arrived on March 11, 2020, when he addressed the nation for the first time on the subject of the pandemic and showed himself to be completely out of his depth. The virus was a fact that Trump couldn’t lie into oblivion or forge into a political weapon—it was too personal and frightening, too real. As hundreds of thousands of Americans died, many of them needlessly, and the administration flailed between fantasy, partisan incitement, and criminal negligence, a crucial number of Americans realized that Trump’s lies could get someone they love killed.

The second event came on November 3. For months Trump had tried frantically to destroy Americans’ trust in the election—the essence of the democratic system, the one lever of power that belongs undeniably to the people. His effort consisted of nonstop lies about the fraudulence of mail-in ballots. But the ballots flooded into election offices, and people lined up before dawn on the first day of early voting, and some of them waited 10 hours to vote, and by the end of Election Day, despite the soaring threat of the virus, more than 150 million Americans had cast ballots—the highest turnout rate since at least 1900. The defeated president tried again to soil our faith, by taking away our votes. The election didn’t end his lies—nothing will—or the deeper conflicts that the lies revealed. But we learned that we still want democracy. This, too, is the legacy of Donald Trump.