-- In a packed convention center, in Columbus, Ohio, Donald Trump divulged what he called one of his greatest fears.
"First of all, it [the primary season] was rigged, and I'm afraid the [general] election is going to be rigged. I have to be honest. Because I think my side was rigged," he said last week of the Republican presidential primaries. "If I didn't win by massive landslides — I mean, think of what we won in New York, Indiana, California 78 percent. That's with other people in the race, but think of it."
He shared a similar sentiment in Davenport, Iowa, Thursday.
"Now we have one left, one left, one left," he said, referring to his Democratic rival, Hillary Clinton. "And in theory, in theory, it should be the easiest, but it's a rigged system. It's a totally rigged system. The elections are rigged."
Trump was known during the primary season for decrying the process as corrupt, railing against the party for undermining him, as he saw it, and claiming that the delegate system worked against him as a party outsider.
It became a rallying cry with many of his supporters who agreed that he was not getting a fair chance. He ultimately felled his primary challengers and became the Republican nominee.
But in these recent comments, he is not only laying the groundwork for explaining a possible loss but also heading down a more pernicious path, instilling in voters a sense that the electoral process is fraudulent and will not work for them.
It's not an unprecedented claim for him to make. In 2012, after Republican then-nominee Mitt Romney lost his bid, Trump went on a Twitter spree. In a tweet now deleted (but archived, thanks to Salon), he said of President Barack Obama, "He lost the popular vote by a lot and won the election. We should have a revolution in this country!"
But this time, his claims are personal and could work to great effect.
Political strategist Roger Stone is a confidant of Trump's but has no formal role in the campaign; the two men, according to sources, speak occasionally. Stone gave an interview to Breitbart News this week in which he laid out how labeling the election as corrupt could help Trump.
"I think we have widespread voter fraud, but the first thing that Trump needs to do is begin talking about it constantly," Stone said. "He needs to say, for example, today would be a perfect example, 'I am leading in Florida. The polls all show it. If I lose Florida, we will know that there's voter fraud. If there's voter fraud, this election will be illegitimate, the election of the winner will be illegitimate, we will have a constitutional crisis, widespread civil disobedience, and the government will no longer be the government.'"
In an interview with ABC News, Stone, a longtime political consultant, said Trump's discussing voter fraud is "absolutely" a smart strategy.
"If you raise this question after you've been cheated, everybody will say you're only challenging the election because you lost. I think you have to get the American people used to the idea that this is a possibility," Stone said.
He said he believes that voter fraud exists in both parties.
But there is very little evidence to suggest widespread voter fraud in general elections.
ABC News contacted Romney's legal team and the Republican National Committee, and neither provided examples of a rigged system in 2012 or other years.
Also, elections are overseen in 40 states by a secretary of state or lieutenant governor; 25 of them are Republican, and 15 are Democrats, according to Election Line, a nonpartisan, nonadvocacy clearinghouse of election information.
David Becker, an election expert at the Pew Charitable Trusts, said, "In 20 years covering elections, I have not seen anything less than the highest level of professionalism by election officials across the country. The voters can feel secure that the results they see on election night represent the true will of the people."
Others agreed. "I'm not quite sure exactly what Mr. Trump had in mind with this statement, but whatever he meant, there is no realistic possibility of the 2016 general election being rigged," said Daniel Tokaji of the Moritz College of Law at Ohio State University. "Voter fraud is extremely uncommon — nowhere near the scale that would change the result of a presidential election in any realistic scenario."
But Trump's supporters are fiercely loyal to him, so simply suggesting the possibility of voter fraud could be enough to cast widespread doubt on the results and in the democratic process itself.
ABC News' Lauren Pearle contributed to this story.