It takes a certain kind of stubbornness to lie about things that are easy to verify.

Donald Trump does it all the time.

During the first presidential debate, he interrupted Hillary Clinton to deny that he had once called climate change a hoax perpetrated by the Chinese. During the second presidential debate, he interrupted her to deny telling America to "check out (the) sex tape" of former Miss Universe Alicia Machado. During the third, the interruption was to deny he'd mocked a reporter with a disability.

He had. The first two were on Twitter; the third had been circulated widely as a video clip. It was stupidly easy to track down the proof.

But instead of letting Clinton make the claim, he felt the need to butt in and deny something that everyone with a computer and 15 seconds could find out was true.

This is the point. Donald Trump lies. All the time.

He doesn’t just stretch the truth in the way most politicians do: selectively citing facts that make them look good, deliberately omitting ones that make them look bad, overstating or understating the probable impact of the campaign promises they make.

No, he just says things that aren’t true. And he knows it. Sometimes it’s something big — routinely, on the campaign trail, he tells voters that he's going to lower everyone's taxes while Hillary Clinton will raise them. Sometimes, it's something so minor — like repeatedly saying he was endorsed "last week" by the union representing immigration enforcement agents, even a month after the endorsement actually happened — that his insistence on lying is all the more infuriating.

It almost seems like it would be easier for Trump to tell the truth. But of all the character flaws that have damaged Trump's candidacy in the final stretch of the campaign, his insistent lying hasn't hurt him much.

Even though fact-checkers deploy their forces on Trump regularly, he never apologizes or retracts. Calling out his lies doesn’t make his supporters any less loyal to him. A substantial number of Americans still find him more "honest and trustworthy" than Hillary Clinton; before the leak of a 2005 Access Hollywood take in which he bragged about being able to grab women's genitals and kiss them without waiting, and subsequent accusations by nearly a dozen women that he'd assaulted them in similar ways, he routinely scored better on "honest and trustworthy" among all voters than Clinton did.

It’s tempting to hold out hope that, at some point, this will all come crashing down: that if Trump were just called to reckoning one more time, or in the right way, his followers would be stripped of their illusions and abandon him en masse.

But on some level, we all know that’s not going to happen.

Donald Trump lies. It’s what he does.

His nonchalant dishonesty is horrifying. The fact that much of the American public simply doesn’t appear to care about his dishonesty — or that they don’t consider it a deal breaker for a potential president of the United States to tell several lies even on his most honest days — is more so.

Donald Trump probably won't win the presidency, but it's not because he lies — and he's made it all the easier for future politicians to lie just as insistently and getting away with it.

We are looking at an existential threat to a key principle of democratic discourse

His supporters may not believe everything he says — in fact, they often say they don’t even think he believes everything he says. They assume that he’s not going to do all the things he promises; the assumption that Trump is a liar is priced into their support of him. The literal things he says matter less to them as facts than as signals that he’s on their side.

We are looking at an existential threat to a key principle of democratic discourse: People can only debate and persuade each other if they agree on the basic facts of the world around them. They are entitled to their own opinions but not entitled to their own facts.

Every single time Donald Trump lies, that principle gets a little shakier and harder to maintain.

Politics isn’t poetry. A statement that is facially false but that hits at an emotional truth is still facially false. And it makes it all the harder for people who respond to the emotional truth to talk to those who don’t — they have no shared basis on which to discuss.

Shared facts should be the bedrock of democracy; Trump is turning it into a Jenga tower.

It’s difficult to overstate just how often, and how blatantly, Trump lies

In September, Daniel Dale, a reporter for the Toronto Star, started posting a list on Twitter of all the provably false statements he hears from Trump on the campaign trail each day. The experience has been both illuminating and exhausting. (He wrote an essay about it for Politico Magazine.)

Over 25 days (starting on September 15 and ending on October 24, with some days off for Dale in between), Donald Trump lied on at least 378 occasions.

It might not be technically fair to call all of these statements "lies" — it’s possible that Trump himself believes them to be true. (And on a couple of occasions, Dale has tallied "lies" that aren't technically falsehoods — like the allegation that Bill Clinton "can't practice law" — and that therefore we haven't counted here.) But at a certain point, his callous disregard for facts crosses the line into criminal neglect.

On debate days, Dale counted at least 30 falsehoods a night. On typical days on the campaign trail, he often counted at least a dozen. In fact, as Trump's gotten closer to Election Day, he's started lying more often — on all but one day Dale's tracked since the second debate, Trump has approached or exceeded the 18-lie mark he set before the first debate.

Even more alarming, while Trump often repeats some of his lies from one day to the next, most of the lies Dale recorded were just told once. Over the 25 days Dale’s recorded so far, Donald Trump has told a total of 212 unique lies.

Trump lies in several distinct ways.

1) He lies about tiny things — like who wrote the song "The Snake" that he likes to recite at his rallies.

2) He lies about crucial policy differences, like saying on 11 separate occasions that his tax plan would cut taxes on the working class and 13 times saying that Hillary Clinton would substantially increase "your taxes."

3) Trump lies about chronology, like the timing of the ICE union endorsement.

4) He turns slights against other people into slights against him: when a hacked email revealed that Hillary Clinton had gotten one question in advance of a Democratic primary town hall, he turned it into an allegation that Clinton was "just recently, word for word, given the questions" to a debate — and sometimes, for good measure, he says she was given the answers as well.

5) He takes facts that should bolster his argument and exaggerates them beyond recognition. The murder rate rose in 2015 — because murder has become so infrequent in the US compared to rates a quarter-century ago, the rise amounted to a 10% jump in the murder rate, which was the biggest percentage increase in 45 years. In itself, that could have bolstered Trump's argument that unrest in America is on the rise. But instead, Trump claims that murders are at a 45-year high.

6) He endorses blatant conspiracy theories. When online conservatives, misinterpreting hacked emails from John Podesta, decided that Podesta was trying to skew the polls by asking an internal pollster to "oversample" Democrats, it took just one day for Trump to espouse the theory — calling it a "form of voter suppression."

7) He lies about things that have no basis in reality whatsoever. Trump has taken to saying on the campaign trail that Hillary Clinton wants "an open border with the Middle East." Where did he get this idea? Who knows. But he said it five times between October 15 and October 24.

8) He obscures the truth by denying he said things he said, or denying things are known that are known. After receiving classified security briefings where (according to reports) the issue of email hacks of Democratic organizations came up, he maintained that they might not have been hacked at all. In debates, he routinely denied the existence of his own ugliest statements. Relatedly, he also claims that things have been "debunked" when they haven't been — like the sexual assault allegations against him.

9) He lies about winning. Trump is probably not going to be the next president of the United States, but you wouldn't know it from listening to his speeches. He says he won the last debate (or, sometimes, the last two debates) "unanimously," when every reliable poll showed he lost them. He cites nonexistent polls to claim he's tied, or leading slightly, wherever he's speaking. (On one occasion, he claimed he was ahead in North Carolina, when 13 consecutive polls had shown him behind.) He claims that Clinton has "given up" on states like Ohio, without evidence.

In one sense, this is the most harmless of all of Trump's lies — either he's right and the polls really aren't telling the truth about his support, or he'll be proven wrong on Election Day, less than two weeks away. But when combined with his fearmongering about a "rigged election" and voter fraud (which, yes, includes more lies), it gets a lot more worrisome. Trump's lies aren't preparing his followers to face the reality that their candidate is probably going to lose the election; they're preparing them to expect a victory, and to get very angry if it doesn't happen. To the extent that Trump's supporters understand that he's not currently favored to win, it's because they're not listening to the candidate himself.

Counting all of Trump's lies can numb you, but every one is a violation

Dale’s efforts have proved that it’s theoretically possible to process all of Trump’s lies, and other news outlets have started to follow suit. Politico magazine, counting both candidates’ tweets as well as speeches and interviews, tallied 87 Trump lies over five days — an average of one lie every three minutes over about five hours’ worth of remarks. (Hillary Clinton didn’t do as much public speaking over the five days Politico tracked, but even if she had, Politico wrote, his lie rate would "still surpass her nearly four times over.")

The Washington Post, doing a qualitative analysis of a week of Trump lies, concluded, "Trump has nevertheless revealed himself to be a candidate who at times seems uniquely undeterred by facts." The headline on the front page of Sunday’s Los Angeles Times read "Scope of Trump’s lies unmatched"; in the article, author Michael Finnegan argued, "Never in modern presidential politics has a major candidate made false statements as routinely as Trump has."

In this context, the analysis of the New York Times seems fairly conservative: It only tallied 31 Trump lies over the last week.

The Times’s analysis ignored smaller lies and instead focused on the lies that "bolstered a powerful and self-aggrandizing narrative depicting him as a heroic savior for a nation menaced from every direction" — creating what Republican strategist Mike Murphy called "an unreality bubble."

If you try to dive into the reasons Trump lies, you’ve already lost. It grants his lies the dignity of a strategy. The truth is that, by all appearances, Trump seems to lie whenever it suits him.

This is why, because Trump lies so nonchalantly and broadly, the practice of tallying his lies can end up being weirdly counterproductive. The more conservative tallies make Trump seem relatively honest; the more comprehensive ones just seem like numbers on a page.

The lies keep coming. And we have no idea what to do about it. And nothing we’ve tried so far has worked.

Here is what you have to remember: Every single time Donald Trump lies, it is a blow to his integrity as a person and his reliability as a potential president.

Every time he tells a second lie in a day, or a third, or an 18th, he makes it harder for the rest of us to reconstitute the body of shared facts on which we can start to debate what’s best for America. It puts everyone who cares about accuracy on the defensive: We are faced with both the moral obligation to speak truth to Trumpery and the growing certainty that nothing we can do will make Trump lie any less.

Trying to fact-check Trump feels like beating your hands against a stone wall until they bleed

Let me be honest with you: For me, as a journalist, this is emotionally exhausting. It is crazy-making.

It is exhausting to have to keep saying, for 15 months now, that no, unauthorized immigrants aren’t more likely than US citizens to be violent criminals.

That seriously, though, the US really does screen Syrian refugees.

Yes, Donald Trump continued being a birther even after Barack Obama released his longform birth certificate.

Look, I know that’s what he says, but really the unemployment rate isn’t 42 percent; it’s less than 5 percent.

Actually, Muslim Americans aren’t "refusing to assimilate" into America — and for Pete’s sake, there weren’t thousands of them cheering on 9/11.

WTF, yes, Russia really is slowly invading Ukraine.

You can see flashes of frustration even among the media outlets most committed to the perception of sober-minded objectivity. The fact that the New York Times, the Washington Post, and a Politico publication all came out with "Trump fact checks" over the weekend before the debate is instructive: Trump has broken their commitment to performed neutrality.

The Times even puts the word "lie" into headlines now when talking about Trump. The CNN chyron has started fact-checking his claims in real time.

Those flashes betray much bigger agonies. The lies keep coming. And we have no idea what to do about it. And nothing we’ve tried so far has worked.

And in poll after poll, Americans find Trump more honest and trustworthy than Hillary Clinton.

All the CNN chyrons in the world, and all the assiduous fact-check tallies, aren’t stopping him from telling lies and aren’t stopping people from supporting a liar. The more explicitly the media calls Trump a liar, the harder it is to ignore the truth: A lot of America simply does not care about his lies.

"Whatever Trump says is true"

Donald Trump didn’t suddenly make it impossible for people who oppose a candidate to persuade his supporters to see "the truth." That’s been happening for a while.

People tend to reject facts that undermine their ideological premises; more informed voters are often more partisan; Americans don’t trust the media, and Republicans (Trump supporters in particular) don’t consume much media that isn’t explicitly conservative. And to a devoted ideologue — or a conspiracy theorist — every fact that appears to undermine your view of the world is just more proof that someone is trying to hide the truth.

It feels like Trump ought to be different; that the relentlessness, nonchalance, and importance of Trump’s lies should be so heavy that they crash through even the most reinforced ideology like a meteor.

But instead, the opposite has happened. Loyalty to Trump is the center of gravity. It is the most important fact.

In polls taken before last week, pluralities of Trump supporters regularly said that President Obama wasn’t born in the United States — parroting the birther conspiracy with which their candidate was associated and that he continued to stoke. Then last Friday, Trump delivered a statement that he’d stopped believing in birtherism in 2011 and that it was actually Hillary Clinton who started the whole thing. These are lies.

Trump supporters — even birthers — were surprisingly supportive. Many of them praised Trump’s trolling of the media by getting them to cover his press conference by teasing a statement on birtherism. And then there was this woman, who, in an interview with Benny Johnson of the Independent Journal Review, expressed it simply: "Whatever Trump says is true."

Asked if she is a birther: "No. If Trump says Obama was born in America he was. Whatever Trump says is true." pic.twitter.com/pbNKzz6kCr — Benny (@bennyjohnson) September 16, 2016

Trump’s supporters take his promises less seriously than some of his critics do

Everyone who’s talked to a lot of Trump voters about their support for Trump — not necessarily alt-right ideologues, but the grassroots Trump supporters who show up to rallies — ends up coming to the same conclusion: A lot of Trump supporters take what Trump says less seriously than some of his critics do.

Many of his supporters simply don’t assume that he’s going to do exactly what he says. In fact, many are confident he won’t.

This isn’t just true of the comments that Trump critics find offensive, and Trump supporters shrug off as simply inartful. It applies to policy.

Donald Trump’s campaign promises? The things he’s ostensibly pledged to do if he is elected president? A lot of Trump critics take those very seriously indeed; it’s a lot of what makes him so scary to, say, many people of color. But many of his supporters simply don’t assume that he’s going to do exactly what he says. In fact, many are confident he won’t.

In May, only 66 percent of Trump voters said they believed he’d build "the wall" — but anecdotally, many Trump supporters have told reporters they think it’s simply "symbolic," a "rhetorical device," or even "a little cray-cray."

In September, 44 percent of Trump supporters said that he wouldn’t succeed at getting Mexico to pay for it — despite the fact that Trump rallies feature a call and response promising just that.

And only 43 percent of Trump voters (as of May) believed Trump would "forcibly deport millions of illegal immigrants" — something Trump promised, then as now, to do. (Sixty percent of Clinton voters took that promise seriously.)

This seems bonkers. These are core issues of the Trump campaign — the things that got a lot of Trump’s supporters to back him to begin with. How can you support Trump and not believe he’ll succeed at building a wall and getting Mexico to pay for it?

Part of the answer is the one Trump occasionally gives himself: that the point of his campaign rhetoric is "a starting point for negotiations." If Trump rides into office demanding a 15-foot-high border wall, the logic goes, he can "compromise" on a 10-foot one.

Many of Trump’s supporters really do believe that the current federal government, under Obama, is doing nothing to secure the border or screen refugees to the US. And many of them believed that before Trump came along.

Even if Trump ends up compromising, the fact that he’s making the demands at all means that something is going to be done.

Taking Trump’s rhetoric as an expression of priorities

Ultimately, though, the appeal of Trump’s rhetoric isn’t necessarily about what he would do at all. It’s about who he would do it for.

Trump’s policy proposals are arguably most coherent if you think of them in terms of choosing sides — and picking winners and losers. Winners: American citizens, particularly those who feel threatened by globalization and cultural change; the police; Russia. Losers: immigrants (particularly unauthorized ones); Mexico; China; Muslims; protesters; countries under the NATO umbrella; corporations that move abroad; the overpoliced.

You don’t need to be a conspiracy theorist to believe that if something you’re doing makes your enemies mad, it means you’re winning

What in particular Trump will do to help the people he favors and hurt those he dislikes is secondary to who comes first. After all, politicians often promise things they can’t deliver. (Democrats promise to appoint Supreme Court justices who will overturn Citizens United, which isn’t a thing they can control.) No one knows what real-life challenges and decisions a President Trump would face over his four or eight years in office. But his fans are confident that whatever decision he makes will be the one that’s best for people like them, not for other people.

Trump’s critics tend to resist believing this. They tend to assume that because Trump is a businessman, and a Republican, he’ll govern with more concern for the needs of big business than for the people who got him to the White House. Or they assume that Trump is out only for himself (possibly true) and therefore will inevitably screw over his supporters (not necessarily true, because he may admire being loved). Trump’s critics know the man is a liar; why would he be honest with anyone?

But to many Trump supporters, it’s a zero-sum world out there. They believe in a "deep story" in which the politicians in charge now consistently put the needs of others — coastal elites, "welfare"-receiving African Americans, immigrants, and refugees — ahead of their own needs. They believe that Trump would turn the tables. And everything he says that upsets and provokes those people is more proof of how big a threat they find him.

You don’t need to be a conspiracy theorist to believe that if something you’re doing makes your enemies mad, it means you’re winning. As writer Ned Resnikoff put it recently, in Trump’s politics, "the only real political choice is selecting the fiction you most prefer."

When Lester Holt called Donald Trump out during the first debate — pointing out that he didn’t actually have to wait until his audit was completed to release his tax returns, and that he actually supported birtherism even after President Obama released his birth certificate — Clinton supporters, and undecided focus-group participants, called it a victory.

Trump surrogates saw it as evidence that Holt was hopelessly biased, and that Trump shouldn’t bother to participate in the next debates at all.

As long as Trump makes it clear whose side he’s on, the literal correctness of what he says isn’t the point. It doesn’t matter to him. Why should it matter to them?

Watch: Donald Trump hates lies, but can't tell the truth