Donald Trump has said he fears the presidential election "is going to be rigged" - an unprecedented assertion by a modern White House candidate.
The Republican nominee's extraordinary claim - which, FYI, he didn't back up with any immediate evidence - would seem to threaten the tradition of peacefully contested elections and challenge the very essence of a fair democratic process.
"I'm afraid the election is going to be rigged, I have to be honest," the Republican nominee told a town hall crowd in Columbus, Ohio.
He added that he's been hearing "more and more" that the election may not be contested fairly. But he didn't elaborate further.
Trump made the claim after first suggesting that the Democrats had fixed their primary system so Hillary Clinton could defeat Bernie Sanders.
The billionaire tycoon has previously backed up that allegation by pointing to hacked emails from the national party - they appeared to indicate a preference for Clinton.
Still, the former secretary of state received 3.7 million more votes than Sanders nationwide. She had established a clear lead in delegates by March 1.
The celebrity businessman also claimed that the Republican nomination would have been stolen from him had he not won by significant margins.
He repeated the charge on Monday night on Fox News, saying: "November 8th, we'd better be careful, because that election is going to be rigged. And I hope the Republicans are watching closely or it's going to be taken away from us."
The statement could be an effort by Trump to lay the groundwork of an excuse if he goes on to lose the election.
But if he were to be defeated in November and then publicly declare that the election results were bogus, his claim could yield unpredictable reactions from his supporters and fellow Republicans.
Trump has not been shy about asserting that the electoral process has been "rigged".
It became a frequent catchphrase of during his primary campaign this spring, when forces allied with Republican rival Ted Cruz managed to pack state delegations with supporters of the Texas senator.
Trump also asserted that the Republican Party had changed the delegate allocation in the Florida primary to favour a native candidate, like Jeb Bush or Marco Rubio, at his expense.
In recent weeks, in an effort to woo angry Sanders supporters to his campaign, Trump has made the claim that the Democrats' process was also rigged.
On Monday night, Trump said Sanders "made a deal with the devil" and said of Mrs Clinton: "She's the devil".