For weeks, as the coronavirus silently spread through the United States, President Trump belittled the threat and repeatedly praised China for “transparency” and the World Health Organization for its handling of the outbreak. But when the death toll mounted and the scope of the public health crisis became too difficult to ignore, Trump reversed course.

“I always felt it was a pandemic long before it was called a pandemic,” he declared — then angrily blamed China for failing to contain the new virus and accused the WHO of helping a coverup. He later withdrew the United States from the WHO.

Likewise, when a distraught widower asked Twitter to remove Trump’s tweets insinuating that the man’s wife had been killed by MSNBC morning host Joe Scarborough, Trump ignored the plea and repeated the slander.

The Trump campaign’s version of the story illustrates a successful — and often inaccurate — picture of the president's response to the coronavirus pandemic. (Meg Kelly/The Washington Post)

The president’s technique — refined over half a century in public life — is relentless and unforgiving: Never admit any error, constantly repeat falsehoods, and have no shame about your tactics.

From the start of Trump’s presidency, The Fact Checker team has catalogued every false or misleading statement he has made. As of May 29, the count stood at 19,127. That works out to about 15 claims per day. But the pace of deception has quickened enormously. He averaged about six claims a day in 2017, nearly 16 a day in 2018, and more than 22 a day in 2019 and 2020 so far. Indeed, the president made more false or misleading claims in 2019 than he did in 2017 and 2018 combined.

The pace and frequency of Trump’s falsehoods can feel mind-numbing — and many Americans appear to have tuned out the torrent of presidential misstatements.

In 2003, George W. Bush’s administration was thrown off course for months, with a top official offering his resignation and a White House aide eventually convicted of perjury, after the president’s State of the Union address included 16 words — “The British government has learned that Saddam Hussein recently sought significant quantities of uranium from Africa” — that turned out to be based on inconclusive evidence.

By contrast, Trump routinely says dozens of things in each State of the Union address, campaign rally and major speech that are flat wrong — with barely any consequence.

As Trump runs for reelection, his unparalleled reliance on misleading and exaggerated claims has emerged as a defining feature of his boundary-busting presidency.

It’s a fool’s errand to try to predict the impact of a presidency while the incumbent is still in office. Each president brings a unique set of skills and personal experiences to the role. Trump’s impact would deepen in a second term; defeat, by contrast, likely would be viewed as a repudiation of his character and approach.

Regardless, it will likely not be known for years if Trump has created a template for future presidents — whether he is an aberration or has changed the nature of the presidency.

There are certainly signs that Trumpism is beginning to influence politics in the United States more broadly. Trump’s aides frequently suggest there is no such thing as absolute, verifiable truth. Kellyanne Conway, the counselor to the president, who advises Trump on policy and communications strategy, coined the phrase “alternative facts” to defend the White House’s false claims about attendance at Trump’s inauguration. Trump’s personal lawyer, Rudolph W. Giuliani, argued that the president should avoid testifying before special counsel Robert Mueller because he could be trapped in a lie that would lead to perjury charges. “Truth isn’t truth,” Giuliani argued, explaining that everyone has their own version of the truth.

At the same time, Trump’s aides have insisted the president does not lie. Stephanie Grisham, Trump’s third press secretary, told The Washington Post in 2019 that Trump doesn’t lie, though sometimes he’s “just kidding or was speaking in hypotheticals . . . he loves this country and he’s not going to lie to this country.” Kayleigh McEnany, Trump’s current press secretary, in a 2019 CNN interview also said firmly and repeatedly that Trump “doesn’t lie. The press lies.”

Trump is not alone on the world stage in deploying this approach. Others do it to an even greater degree. Russian President Vladimir Putin offers up a fog of disinformation to maintain power, including denying obvious facts (such as Russian involvement in the downing of Malaysia Airlines Flight 17), spouting falsehoods and deflecting attention with nonsensical comparisons (dubbed “whataboutism”).

“A cumulative effect of all these tactics is nihilistic debasement of the very concept of truth,” said Michael McFaul, a former U.S. ambassador to Russia. “Putin is not trying to win the argument; instead, his propaganda machine aims to convince that there is no truth, no right and wrong, or no data or evidence, only relativism, point of view and biased opinion.”

Trump used all three tactics to combat the investigation that led to his impeachment. He denied verified facts; he said he halted military aid to Ukraine because of concerns about “corruption,” but the Defense Department had already certified that Ukraine had met anti-corruption targets, Trump never raised the issue of corruption in his phone call with the Ukrainian leader, and the White House conducted no review of corruption in Ukraine while the aid was on hold. He told easily disproved falsehoods, such as claiming that the White House whistleblower wrote “a fake report” when it was correct on virtually all details. And he regularly engaged in whataboutism, seeking to direct attention to the actions of former vice president Joe Biden’s son Hunter, even though Hunter’s business dealings, if suspect, were irrelevant to whether Trump abused power.

The president is aided in his disinformation effort by cheerleaders in the right-leaning media, especially evening talk show hosts such as Sean Hannity and Lou Dobbs on Fox News and Fox Business, respectively, as well as Republican lawmakers who generally refuse to criticize his actions publicly. The few GOP lawmakers who have dared to challenge the president’s falsehoods have quickly found themselves under attack, either from the president’s Twitter account or by his fervent supporters. Rep. Justin Amash of Michigan read the Mueller report and declared it was clear that the president should be impeached. Amash was immediately drummed out of the Republican Party and became an independent. He ended up voting for Trump’s impeachment.

Trump has targeted traditional news media organizations as unreliable, corrupt, “fake news” and “the enemy of the people.” His aim is to undermine straight reporting that uncovers malfeasance, corruption or unflattering information. Trump appears to view any critical story as “fake news,” even if it’s true. Without evidence, he accuses news organizations of making up sources — even though that would be a firing offense at any reputable media outlet.

Trump was elected expressly to disrupt the norms of Washington, and he has consummate confidence in his direct link to his supporters — his use of social media to promote his personal brand. Just as Franklin D. Roosevelt harnessed the power of radio with regular “fireside chats” and John F. Kennedy was the first made-for-television president, Trump has shown politicians around the world how to make an impact with a well-timed tweet. Future presidents may be a bit more circumspect in their rhetoric on Twitter — and whether they use it to spread falsehoods and attack rivals — but they certainly will not ignore the power of social media to make their case. Besides Twitter, Trump has mastered Facebook, microtargeting supporters to keep them engaged and supportive — and going after political rivals.

Trump’s attacks on the media have been effective enough that some of his allies have adopted his tactics. When a CNN reporter tried to ask Sen. Martha McSally (R-Ariz.) a straightforward question about calling witnesses in the impeachment trial, she responded: “You’re a liberal hack. I’m not talking to you. You’re a liberal hack.” McSally, who was facing a tight election race, immediately posted the exchange on YouTube and used it to raise money. Her reward? A tweet from a Trump 2020 Twitter account: “THIS is how you handle FAKE NEWS.”

Similarly, Secretary of State Mike Pompeo publicly attacked as a “liar” a co-host of NPR’s “All Things Considered,” Mary Louise Kelly, when she brought up Ukraine in an interview that he claimed was supposed to be devoted only to questions on Iran. She proved Pompeo was the liar when she revealed emails showing that she had told his staff she would ask about Ukraine.

Trump offers supporters a binary choice: You are with me, or you are not. That simplistic approach takes advantage of how Americans increasingly view party identification as a basic, essential sign of character.

In 1960, a survey found that only 4 percent of Democrats and 4 percent of Republicans said they would be disappointed if their child married someone from the opposite political party. In a 2019 survey, 45 percent of Democrats and 35 percent of Republicans said they would be somewhat or very unhappy if their son or daughter married someone from the other party. A child’s decision to marry someone from a different race, ethnicity or religion raised far less concern, especially among Democrats.

Trump’s presidency is both a product of this tribalism and an exacerbating force. Going far beyond the traditional rhetorical flourishes politicians use to rally supporters, Trump routinely depicts Blue America as evil. “Democrats are now the party of high taxes, high crime, open borders, late-term abortion, socialism and blatant corruption,” Trump declared at a January 2020 rally. “The Republican Party is the party of the American worker, the American family and the American Dream!”

By exploiting this sense of grievance against the Other — whether that means the other party, people of other races or ethnicities, or people with different values — Trump makes it easier for his supporters to ignore or even embrace his falsehoods.

This attitude might help explain why Trump retains such a hold over his core group of supporters, despite constant chaos in the administration, relatively few domestic or foreign policy accomplishments — and a persistent inability to tell the truth.

But there are also signs that Trump may be an aberration — and that once he leaves the White House, either in defeat in 2020 or at the end of a second term, no other president would consider lying on such a grand scale.

Every action in politics results in a reaction, so the immediate consequence of Trump may be a successor who distinguishes himself from Trump by refusing to engage in hyperbole and falsehoods.

Richard Nixon, after all, was soon followed by Jimmy Carter, who assured voters during his 1976 campaign that “I’ll never tell a lie. . . . I’ll never knowingly make a misstatement of fact. I’ll never betray your trust. If I do any of these things, I don’t want you to support me.”

Similarly, Democrats running for their party’s nomination to face Trump emphasized truth-telling, even if their records on this front weren’t perfect. For instance, Sen. Kamala Harris (D-Calif.), who dropped out before any primary votes were cast, titled her 2019 campaign memoir “The Truths We Hold” and included the line “Let’s speak truth” in her stump speech.

More broadly, there is evidence that Trump’s falsehoods may have hurt him more than they have helped him. That may limit the appeal for other politicians to follow his path. Trump may have survived impeachment with a blizzard of falsehoods, but through the first three years of his term, he failed to ever win support from a majority of Americans in public opinion polls.

A 2019 Gallup poll found that by a narrow margin, 51 to 49 percent, Americans considered Trump “a strong and decisive leader.” But only 34 percent believed he “is honest and trustworthy,” what Gallup described as “among his weakest personal characteristics.” Trump has earned 33 or 34 percent on the trustworthiness question throughout his presidency. By contrast, Americans were more likely to consider George W. Bush (65 percent), Barack Obama (61 percent) and Bill Clinton (46 percent) honest and trustworthy.

Paradoxically, Trump’s attacks appear to have helped revive trust in the media, which had been falling for decades and reached a low in 2016. During the Trump presidency, trust in the media jumped substantially, especially among Democrats, though it dipped from 2018 to 2019, according to Gallup. Trust in the media also went up for both Republicans and independents from 2016 to 2018 but slipped back in 2019, with Republicans at nearly the same level as in 2016. The same poll showed a sharp partisan divide: “Fox News is the only national news source with majority-level trust from Republicans while majorities of Democrats trust six national news sources,” Gallup said.

For a president, such low marks on trustworthiness undermine his authority and make it harder to rally public support for his domestic proposals and foreign policy initiatives. Trump’s proclivity for exaggeration and falsehoods has made it more difficult for him to build popular consensus even for his most successful actions.

Telling the truth and being open to new information that challenges your preconceptions is the best policy for most people. It turns out that is also the best option for politicians seeking broad public support.