In their personalities and their politics, Hillary Clinton and Donald Trump might not have much in common, but in the public eye they share one glaring characteristic: A lot of people don’t believe what they say. In a July New York Times/CBS poll, less than one-third of respondents said Clinton is honest and trustworthy. Trump’s scores were about the same.

Trump’s campaign-trail falsehoods are so legion that cataloguing them has become a journalistic pastime. With a cocky disdain for anything as boring as evidence, the presumptive GOP nominee confidently repeats baseless assertions: He purports to have watched American Muslims celebrate the Twin Towers’ fall; he overstates the sizes of the crowds at his rallies, he understates America’s GDP growth rate, and no reputable business publication agrees with his claims of a personal net worth of $10 billion. In March, when three Politico reporters fact-checked Trump’s statements for a week, they found he had uttered “roughly one misstatement every five minutes.” Collectively, his falsehoods won PolitiFact’s 2015 “Lie of the Year” award. Conservative New York Times columnist David Brooks has judged Trump “perhaps the most dishonest person to run for high office in our lifetimes.”

Clinton isn’t an egregious fabricator like Trump, but she’s been dogged her whole career by a sense of inauthenticity—the perception that she’s selling herself as something she isn’t, whether that’s a feminist, a liberal, a moderate or a fighter for the working class. Detractors, especially on the right, have deemed her dishonest about the facts as well. In 1996, New York Times columnist William Safire called her a “congenital liar,” and decried as utterly implausible Clinton’s statements about commodities trading, the firing of White House travel staff and the investigation of Vince Foster’s suicide. Although unfounded, his charges stuck. Feeding the image of a prevaricator, Clinton has also waffled on or modified her policy positions over the years on issues ranging from free trade to gay marriage. And that doesn’t even include the ongoing investigation of the private email server she used during her tenure as secretary of state, and her highly disputed statements about whether and how it conflicted with government rules.

As Trump and Clinton head into a general election battle, it’s tempting to despair that political lying has reached epic proportions—that the venerable institution of the American presidency is about to be smothered in a blizzard of untruth. But there’s no need to panic: Lying has a long and distinguished lineage in American presidential politics, and the republic has survived. As much as we’d like to imagine it, there was never a time when our democratic debates adhered to the standards of the courtroom or the lie-detector test. As the philosopher Hannah Arendt wrote in a classic 1967 essay, “No one has ever doubted that truth and politics are on rather bad terms with each other.”

Yet persistence of presidential lying doesn’t mean that our politics are morally bankrupt. Yes, democracy demands that the people know the truth about what their leaders are doing, and what their potential leaders intend. Some lies hide information that the public ought to know; others can sow false or dangerous beliefs. A pattern of premeditated duplicity—or even a cavalier disregard for the facts—can bespeak a character ill-suited for democratic leadership. ...