The "big lie" is the favored propaganda technique of history's worst dictators: Repeat a lie loudly, over and over until people come to believe it. Republican nominee Donald Trump Donald John TrumpOmar fires back at Trump over rally remarks: 'This is my country' Pelosi: Trump hurrying to fill SCOTUS seat so he can repeal ObamaCare Trump mocks Biden appearance, mask use ahead of first debate MORE has now brought the big lie to America with his claim that Democratic nominee Hillary Clinton Hillary Diane Rodham ClintonButtigieg stands in as Pence for Harris's debate practice Senate GOP sees early Supreme Court vote as political booster shot Poll: 51 percent of voters want to abolish the electoral college MORE is rigging the election against him through widespread fraud at the polling place.

Ever since 1800, when Thomas Jefferson defeated John Adams in the first presidential transfer of party power, candidates have graciously conceded defeat and fostered the peaceful transition that anchors American democracy. Even Richard Nixon rebuffed the suggestions of advisers to challenge results of his razor-thin loss in 1960.

Now Trump has broken with that tradition, even before the election results are in.

Of course there is large scale voter fraud happening on and before election day. Why do Republican leaders deny what is going on? So naive! — Donald J. Trump (@realDonaldTrump) October 17, 2016

Although Trump claims that voter fraud is "very, very common," every available study, including one by the Republican National Lawyers Association (RNLA) that set out to find as much fraud as possible, has shown that voter fraud is vanishingly small. Republican campaign lawyer and RNLA member Chris Ashby said that "Donald Trump's attacks on our system of voting are unfounded," and also have "the potential to have a destabilizing effect on the orderly administration of the election."

Robert Kelner, another lawyer who has worked for Republican campaign organizations, added that ironically, "The only real threat to this election is the reported effort by Russian intelligence services to hack election systems, which is something that Trump himself has failed to condemn."

A recent study of voter impersonation at the polls — the kind of fraud to which Trump most frequently refers — by Professor Justin Levitt of the Loyola Law School, Los Angeles, found precisely 31 credible cases out of more than 1 billion ballots cast nationwide from 2000 to 2014.

That's about one fraud case per 33 million votes.

In the context of lawsuits challenging voter photo identification requirements in the states of Texas, North Carolina, Pennsylvania and Wisconsin, Republican state officials made every effort to find widespread voter impersonation. They came up empty.

In his opinion in the Pennsylvania case, for example, State Judge Bernard McGinley noted that the state had conceded "that there were no specific incidents of voter fraud underlying passage of the Voter ID law."

Yet Trump contends that Philadelphia is a hotbed of voter fraud. Similarly in Wisconsin, Federal Judge Lynn Adelman found that "defendants could not point to a single instance of known voter impersonation."

The two pieces of evidence that the Trump campaign has used to buttress its claim of a rigged election have nothing to do with voter fraud and certainly not with the deliberate rigging of an election. The campaign cites a Pew Charitable Trusts report showing numerous errors on voter registration lists. But Pew never links these errors to any successful or even attempted voter fraud.

The campaign also cites a study by two political scientists purporting to show that some non-citizens have voted in U.S. elections. Yet this study has been thoroughly debunked by authorities in the field. An article in Electoral Studies found that the study's results "are completely accounted for by very low frequency measurement error; further, the likely percent of non-citizen voters in recent US elections is 0." Even taking the study at face value, the authors do not claim that non-citizen voting results from systematic fraud rather than human error.

After asking the Trump campaign for its best evidence of "large scale voter fraud," PolitiFact gave Trump's charge its worst-possible "pants on fire" rating.

Trump: "Of course, there is large scale voter fraud happening on and before election day." https://t.co/VDz3yy8uDw pic.twitter.com/WRpz1ogS6S — PolitiFact (@PolitiFact) October 17, 2016

Yet the big lie is taking hold. A Politico/Morning Consult poll found that 41 percent of voters believe that the election could be "stolen" from Trump through widespread voter fraud.

Trump's big lie is rendered yet more incredible by the fact that Republicans control the administration of elections in most key battleground states, including three of the four states on which Trump has focused his campaign: Florida, Ohio and North Carolina. Jon Husted, the Republican secretary of state of Ohio who said he is voting for Trump, refuted allegations of a rigged election. "I can reassure Donald Trump, I am in charge of elections in Ohio and they’re not going to be rigged," he said. Our electoral system "is actually more secure than it ever has been."

Trump's use of the big lie confirms what we already know about him from his bankruptcies, his stiffing of small business owners, and the machinations of Trump "University" and the Trump Foundation.

First, Donald Trump takes no personal responsibility for anything he says or does. Second, Trump cares about one thing only: himself. If he wins the election, great; if he loses, he wouldn't really have the lost because Hillary Clinton stole his victory from him. Never mind the damage he has wrought to our democracy.

Lichtman is a distinguished professor of history at American University in Washington.

The views expressed by contributors are their own and not the views of The Hill.