Delaware, Ohio (CNN) Donald Trump said Thursday he will accept the results of next month's election if he wins, a caveat that threatens to cast unprecedented doubt on the legitimacy of the electoral process.

Trump offered a stunning declaration during the final presidential debate that he might not accept the results of next month's election. In his first speech since the debate, Trump seemed to simultaneously double down on the stance he articulated Wednesday night while also trying to clean it up.

Trump argued forcefully during a rally here that he was being asked to "waive" his right to contest the election after critics slammed him for refusing to pledge to accept the results of the election the previous night during the final presidential debate.

"I would like to promise and pledge to all of my voters and supporters and to all of the people of the United States that I will totally accept the results of this great and historic presidential election, if I win," Trump told supporters here in his first comments since the final debate.

After raising concerns about voter fraud -- instances of which are extremely rare -- Trump also pledged to accept "a clear election result."

"Of course, I would accept a clear election result, but I would also reserve my right to contest or file a legal challenge in the case of a questionable result," Trump said. "And always, I will follow and abide by all of the rules and traditions of all of the many candidates who have come before me. Always."

His running mate, Indiana Gov. Mike Pence, echoed Trump's comments while speaking in Reno, Nevada, telling supporters: "Of course, we will accept a clear election result, but we also reserve the right to contest or file a legal challenge in the case of questionable results."

'I will keep you in suspense'

Trump's remarks Thursday appeared aimed at quelling the outrage he sparked the previous night as Republicans and Democrats alike balked at Trump's response that "I will look at it at the time," when asked if he would concede the election should he lose on November 8. But by refusing again Thursday to promise outright that he will abide by the results of the election, Trump kept alive a worrying conspiracy theory that his underdog candidacy could be defeated by below-board behavior.

The remarks came after Trump took intense fire from Republicans and Democrats alike for saying "I will look at it at the time," when asked if he would concede the election should he lose on November 8.

"I will keep you in suspense," he added during the debate.

Trump also said Thursday that he was only refusing to make a blanket statement concerning the results of the election because he wants "fairness during the election."

"This is having nothing to do with me but having to do with the future of our country. We have to have fairness," he said.

Trump, who has spent weeks calling the election "rigged" and suggesting to his supporters the presidency could be stolen from them, sought to compare his situation to the 2000 election, when Al Gore sought a recount in several counties after the results of the election in Florida were very tight.

"If Al Gore or George Bush had agreed three weeks before the election to concede results and waived their right to a legal challenge or a recount then there would be no Supreme Court case," Trump said of the ensuing legal process following the contested result of the 2000 election.

But neither Bush nor Gore raised concerns about the legitimacy of the electoral process, neither before nor after Election Day. And a day after the Supreme Court ruled, Gore called Bush to concede.

Trump's pledge to accept the results of the election "if I win" could have gone differently on Thursday, based on prepared remarks the Trump campaign released after his speech concluded.

The prepared remarks of that "major announcement" offered a similar, and seemingly more lighthearted, pledge labeled "ALTERNATE."

"I would like to promise and pledge to all of my voters and supporters, and to all of the people of the United States, that when the results come in on election night, I will accept -- without delay or hesitation -- the concession speech of Hillary Rodham Clinton," read the alternate text of Trump's pledge to accept the presidential election results if he wins.

The question about accepting the election's results was posed to Trump on Wednesday night after the Republican nominee spent weeks arguing that there was a mass "establishment" conspiracy seeking to undermine his candidacy.

Trump's talk of a "rigged" election came after nearly a dozen women came forward last week alleging that Trump had groped or kissed them without their consent -- prompting a deluge of defections from Republicans who had been supporting his campaign and unfavorable media coverage.

But in previous months, Trump had already begun suggesting to his supporters that the election could be stolen, urging them to be vigilant on Election Day and watch for cases of voter fraud, which are extremely rare in the US.