WASHINGTON — Donald Trump this week foreshadowed — with his baseless accusation of widespread voter fraud in the presidential election — that he could bring his well-documented habit of telling whoppers into the Oval Office.

Trump, who in 52 days will assume the most powerful office in the land, is taking the country into uncharted territory, a Twitter-age president-elect who historians say is on track to alter expectations of trustworthiness and factual integrity in government.

“One would assume that when Trump got the nomination and won the election, that he would upgrade his act,’’ said Douglas Brinkley, a presidential historian and professor at Rice University. “But I don’t know if he has the ability to stop himself.’’

The fact-checking news site PolitiFact has reviewed 335 statements that Trump has made since his campaign started, and found only 15 percent were rated true or mostly true — a far lower record than President Obama. More than half of Trump’s statements were deemed false by PolitiFact or, given the most untruthful rating, “pants on fire.’’ Of the four statements reviewed since his Nov. 8 election as president, one was “pants on fire,’’ two were false, and one was “half true.’’

Now it’s not just the candidate’s credibility at stake. The reputation of the United States will be on the line. Any statement from the White House carries the potential to influence global financial markets and world diplomacy.

Nancy Koehn, a historian and professor at Harvard Business School who specializes in analyzing leadership, said Trump’s reliance on innuendo and conspiracy could erode confidence in the American democracy, which in turn, would “drive a very dark spike through the Republic.’’

“If this behavior continues, we can expect American society to be denigrated, and our kids to learn a whole bunch of lessons we don’t want them to learn,’’ Koehn said. “All kinds of fissures and cracks will emerge in our social stability.’’

Many politicians color the truth, of course, and untruths from the Oval Office and other quarters of government has a long, bipartisan history. Erroneous information was used to justify war, including the murky Gulf of Tonkin incident as a trigger for American attacks on North Vietnam and the pursuit of nonexistent weapons of mass destruction to justify war against Iraq. Bill Clinton famously declared that he did not have sex with White House intern Monica Lewinsky.

But the best analogy for Trump, according to historians, is Richard Nixon, who mused about conspiracy theories and spewed racism that was recorded by his infamous Oval Office taping system.

But, unlike Nixon, Trump is not recording his unsubstantiated thoughts for posterity. He is actively broadcasting them to the world, live.

“There’s something Nixonian about Trump’s tweets,’’ Brinkley said. “But with Trump, we have the potential to see the dark recesses of his mind in real time, and that’s scary.’’

Since the election he said he was canceling a meeting with The New York Times because the Times changed the ground rules (it didn’t), and that he successfully fought to keep a Ford plant in Kentucky (it wasn’t moving anyway). The biggest whopper came Sunday when he claimed — with no evidence — “millions of people’’ voted illegally in the election. Furthermore, he said, if those votes hadn’t counted, he would have won the popular vote, which Hillary Clinton leads by more than 2 million votes.

Trump also wrote on Twitter that there was “serious voter fraud in Virginia, New Hampshire, and California — so why isn’t the media reporting on this? Serious bias — big problem!’’

On Monday night, he went on another tirade, retweeting four random users — including someone who claimed to be a 16-year-old from Beverly Hill, Calif. — who criticized CNN’s coverage of his allegations of voter fraud.

California’s secretary of state, Alex Padilla, said the voter fraud allegations are “absurd.’’

“His reckless tweets are inappropriate and unbecoming of a president-elect,’’ Padilla wrote on Twitter.

New Hampshire’s deputy secretary of state, Dave Scanlan, also discounted Trump’s allegation, saying the state had fielded only “isolated complaints.’’

Legal analysts have consistently concluded that voter fraud is extremely rare, and widespread voter fraud across multiple states remains almost impossible.

“We’ve heard this before and it has been debunked dozens of times and it just keeps being repeated,’’ said Gerry Hebert, director of voting rights at the Washington-based Campaign Legal Center.

Trump has not said where he received the alleged information regarding voter fraud. The president-elect has not held a press conference since July 27 to take open questions from reporters.

The allegation about 3 million fraudulent votes can be traced to Infowars.com, a conspiratorial website run by Trump supporter and conservative rabble-rouser Alex Jones.

Previously, Jones has come under fire for saying that he believes that the 2012 shooting at Sandy Hook Elementary School in Connecticut, in which more than 25 people were killed, including 20 children, was a staged event.

For the allegation about the 3 million illegal votes, Jones cited Gregg Phillips, a former conservative operative. When pressed for evidence of voter fraud on his Twitter feed, Phillips linked to a statement from True the Vote — an organization that he says he’s a board member of — stating that it will present a “comprehensive study’’ on widespread voter fraud in “several months.’’

True The Vote has not responded to a request for comment on the timetable for that study.

Republicans and Democrats alike were at a loss Monday to defend Trump’s claims.

“I don’t know what he was talking about on that one,’’ Senator James Lankford, a Republican from Oklahoma, told CNN, adding that he had ‘‘not seen any voter irregularity in the millions.’’

“I think what I can say is an objective fact, is that there has been no evidence produced to substantiate a claim like that,’’ White House press secretary Josh Earnest said during a briefing.

Governor Terry McAuliffe of Virginia, a Democrat, laughed, saying there wasn’t a single instance of voter fraud in his state.

During Obama’s presidency, nearly 600 claims have been fact-checked, and his record is just the opposite of Trump’s: Nearly half were judged true or mostly true by PolitiFact, while 14 percent were false or “pants on fire.’’ Hillary Clinton’s record is similar to Obama’s.

“I feel at a loss for words when he says things that seem to be conspiracy theories with no evidence. We do the checks and say there’s no evidence here. But wow, it’s strange,’’ said Angie Drobnic Holan, editor of PolitiFact. “We’re in a new era of sorts.’’

Other politicians, she said, will often change their rhetoric after being called out for pushing dubious information.

“Obama, we’ve noticed over the years, will change talking points to make them more accurate, whereas Trump will double down on things that have been debunked,’’ she said. “My sense is that Obama personally cares about facts and honesty and he’s talked about this. My sense is that he tells his staff he doesn’t want errors of fact in his prepared remarks. And we don’t find that many.’’

White House speechwriters tend to footnote every fact, and a draft of every speech is saved so that each revision exists as an official record. Press releases and official statements go through multiple levels of review.

When representatives of the administration step forward, they have typically tried to hew to agreed-upon facts, even while offering up the White House point of view.

“As press secretary, I would be instantly challenged by a vigorous press corps, plus crowd-sourcing on live TV, if I said something factually wrong,’’ said Ari Fleischer, the press secretary under President George W. Bush. “It’s a great way to be certain you do your homework first before speaking. I often recall asking my staff to ‘show it to me,’ or I would press them on a fact, before I was willing to say it from the podium.’’

Matt Viser can be reached at matt.viser@globe.com. Astead W. Herndon can be reached at astead.herndon@globe.com.