Mr Trump has left his stunned allies struggling to defend his refusal at the final presidential debate to say if he would honour the results of the November election should he lose, sparking condemnation from both Republicans and Democrats.
His comments came as a tenth woman came forward claiming the Republican nominee had groped her.
Mr Trump kicked off a rally in Delaware, Ohio, by saying that he “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”.
But he added: “If I win.”
He went on to say: “I will accept a clear election result, but I will also reserve my right to contest and file a legal challenge in the case of a questionable result.”
Mr Trump continues to raise concerns about the integrity of the election, despite a lack of evidence of widespread voter fraud in the country.
With the elections less than three weeks away, Mr Trump insists Democratic rival Hillary Clinton’s campaign team and the media are attempting to rig the vote against him.
Asked point-blank during Wednesday’s debate whether he would accept the results no matter what, he said: “I’ll tell you at the time. I’ll keep you in suspense, OK?”
Ms Clinton said she was “appalled” by what she called as an attack on US democracy.
Republican senator John McCain, who lost the 2008 presidential election to Barack Obama, said he had conceded defeat “without reluctance”, even though he did not like the outcome.
Mr McCain said he did not know who would win this presidential election, but added that the loser has always congratulated the winner and called him “my president”.
“That’s not just the Republican way or the Democratic way,” said Mr McCain said: “It’s the American way. This election must not be any different.”
Mr Trump’s comments came just hours after his running mate, Indiana governor Mike Pence, said: “We’ll certainly accept the outcome of this election.”
And Mr Trump’s daughter Ivanka, arguably his most influential adviser, said on Wednesday that her father would “do the right thing” when she was asked if he would concede after a defeat in November.
The debate answer left his own team scrambling in the aftermath. Campaign manager Kellyanne Conway at first responded to questions about the comment by saying he “would accept the result, because he’ll win the election”.
“So, you know, absent widespread fraud and irregularities, then, we’ll see,” Ms Conway said.
“What he’s saying is we have to see what happens.”
Meanwhile, another woman came forward yesterday accusing Mr Trump of “inappropriate sexual conduct” in a press conference called by women’s rights attorney Gloria Allred.
Ms Allred introduced Karena Virginia, a yoga teacher and “inspirational speaker”, at the London Hotel in Manhattan — within walking distance of the famed Trump Tower.
“After Donald Trump was caught on tape bragging about groping women, a number of women came forward to share their experiences,” said Ms Virginia.
“I am here today to add my voice to that of the other Trump accusers. I am here to stand up to Mr Trump for myself, my family, particularly my daughter, and for all the women who deserve to be respected and not subjected by sexual abuse or groped by powerful men who believe that women can be groped, grabbed, or kissed at their pleasure.”
Ms Virginia said she came forward to support the other women who were courageous enough to share their stories. She also said no one had asked her to come forward and that many people advised her to keep quiet, saying Mr Trump would likely deny the claims and brand her a liar, as he has done with others who made claims against him.
She said she met Mr Trump by chance while waiting for a lift in Flushing, Queens, outside the US Open in 1998. She was 27 at the time. Mr Trump was 52.
“He then walked up to me and reached his right arm and grabbed my right arm,” she said. “Then his hand touched the right inside of my breast. I was in shock. I flinched. ‘Don’t you know who I am?’ That’s what he said to me. I felt intimidated and I felt powerless.
“Then my car pulled up and I got in. After I closed the door, my shock turned to shame. I felt ashamed that I was wearing a short dress and high heels. That feeling of shame stayed with me for a while, and it made me disinclined to wear short dresses or high heels.
“For a number of years afterwards, I struggled with what to wear so as to not attract unwanted attention.”
Ms Virginia’s claim comes a day after the third and final presidential debate between Mr Trump and Ms Clinton.
“Today’s victim is also noteworthy in that her allegation demonstrates how Mr Trump selects his victims at random,” said Ms Allred. “Some of the women, including the woman who is here today, had an encounter with Mr Trump that appeared to be strictly by chance.”
Ms Allred said Mr Trump can no longer claim that he respects women.
Petulance undermines debate performance
The final US presidential debate was Donald Trump’s last chance to make his case for winning the White House, but instead he gave the finger to democracy by refusing to say that he would accept the choice of the American people on election day.
When asked the first time by moderator Chris Wallace if he would respect the result, Mr Trump replied: “I will look at it at the time.” When pressed again, he replied: “What I’m saying is I’ll tell you at the time. I’ll keep you in suspense, OK?”
His Democratic rival, Hillary Clinton, called his response “horrifying”.
At last night's debate, Trump showed again and again that he doesn't have a clue about what makes America great. https://t.co/r5oDWYARU6— Hillary Clinton (@HillaryClinton) October 20, 2016
Last night, Mr Trump said he would accept a clear election result, but stated he would “also reserve my right to contest and file a legal challenge in the case of a questionable result”.
Certainly, his remarks are an unprecedented rejection of the very cornerstone of democracy.
It was far more serious than any of the many incendiary remarks he has made during his campaign about immigrants, women, the disabled, and minorities because, for the first time on a public stage at a US presidential debate, a line was crossed and the whole process that underpins democracy was casually jettisoned.
Some in the Trump camp later defended the Republican nominee by asserting that Democrat Al Gore did the same thing by not immediately conceding the 2000 election to George W Bush.
However, Mr Gore held out because that election was too close to call due to a dispute over the Florida count but he did concede when the Supreme Court stepped in and stopped the Florida recount, making Mr Bush the winner.
In a way, Mr Trump’s refusal to say he would accept the result was merely an extension of his repeated assertions during the debate and earlier that the election was being “rigged” and voter fraud could be expected.
Yet a recent study by Justin Levitt, an expert in constitutional law and democracy at the Loyola Law School in Los Angeles, found that, out of more than 1bn votes cast between 2000 and 2014, there were just 31 instances of voter fraud.An earlier study by the Brennan Center for Justice at New York University Law School also found fraud to be “extraordinarily rare” and said the rate of substantiated instances of such fraud ranged between 0.00004% and 0.0009%.
It remains to be seen whether Mr Trump’s continued assertions about vote rigging, coupled with his refusal to say he would accept the election outcome, will doom his already lagging presidential chances but it will likely dominate discussions about his candidacy in the days ahead.
This was certainly not the message he needed coming out of the debate because, ironically, this was probably his best performance to date.He looked and sounded calmer, more disciplined, and better prepared than in the two previous debates, especially during the first 40 minutes, scoring a number of points against Clinton.
He made the case for change and punched home some good points on trade and the economy. He also forced Ms Clinton to dodge and dive as she sought to defend perceived conflicts of interest involving the Clinton Foundation and its acceptance of donations from countries such as Saudi Arabia.
He said it was a criminal enterprise, which she denied, and as a result she should not have been allowed to seek the presidency.
The candidates also had a spirited exchange on abortion, gun control, and immigration. He delivered standard conservative responses on the Supreme Court and the kind of judges he would appoint if elected, though he did not explicitly say he wanted to see the landmark Roe v Wade ruling on abortion rights overturned.
If he had continued in this vein he would likely have won himself more support from Republicans outside his base, whom he now desperately needs,as he falls further behind Clinton in national polls though the race is tighter in some battleground states.B but it did not last and he probably did not help his case when his remarks in a 2005 video about being free to grope women because he was a “star” resurfaced.
While he again said the sex assault allegations against him were “totally false”, he went on to say the women were just seeking “fame” or were orchestrated by the Clinton campaign.
As in the previous two debates, he interrupted Ms Clinton repeatedly and, while she was discussing social security, he interjected: “Such a nasty woman.”
A CNN/ORC poll at the end of the debate declared Ms Clinton the winner — 52% to 39%.
Nevertheless, Mr Trump has succeeded in cutting her margin of victory in the two debates this month compared with the first one in September.
But any points he scored against Clinton will soon be forgotten and what this debate will be most remembered for is his failure to endorse the voting process that he would be sworn to defend if elected to lead the most powerful democracy in the world.
Clinton proves cool, competent, and in control
This wasn’t a spectacular presidential debate for Hillary Clinton but she did what she had to do — she was calm, competent, and in control in pressing her case for the White House against Donald Trump.
But by maintaining a cautious, lawyer-like approach, she may have lost a key opportunity to broaden her voter base further with an inspiring message around her candidacy in the last weeks of her campaign.
She went into this final debate with a strong wind at her back in the polls, so she could have afforded to take more chances.
It is not enough for her to simply seek refuge in polls that show voters increasingly perceive her as a safer choice for the White House than Trump. She needs to project fresh enthusiasm and make a final compelling pitch to voters.
If Clinton does take the White House, she will need to win by the kind of margin that would make a mandate unquestionable and serve to mute menacing talk among some opponents about “de-legitimatising” a victory.
To do that she needs to show she has a warm heart as well as a safe pair of hands. But at the end of the final debate, she essentially left her heart out of it, except for one exchange about women’s rights and abortion rights in which she showed rare depths of passion.
Discussing her support of the 1973 Roe v Wade Supreme Court ruling on abortion rights, which a Trump court would seek to overturn, she said the following: “I strongly support Roe v Wade, which guarantees a constitutional right to a woman to make the most intimate, most difficult in many cases, decisions about her health care that one can imagine.
“And in this case it’s not only about Roe v Wade. It is about what’s happening right now in America. So many states are putting very stringent regulations on women that block them from exercising that choice to the extent that they are defunding Planned Parenthood, which, of course, provides all kinds of cancer screenings and other benefits for women.
“Donald has said he’s in favour of defunding Planned Parenthood. He even supported shutting the government down to defund Planned Parenthood. I will defend Planned Parenthood. I will defend Roe v Wade, and I will defend women’s rights to make their own health care decisions.”
She also managed to deflect or sidestep issues dogging her campaign involving WikiLeaks revelations, focusing on emails from her campaign chairman John Podesta, which were leaked after what US intelligence agencies believe was a Russian government hack.
If she felt vulnerable, she didn’t show it and instead turned the Wikileaks controversy into an attack on Trump, suggesting he was a “puppet” of Russian president Vladimir Putin.
Indeed, after a more passive performance in the second debate, she reverted this time to her first debate strategy of needling Trump as much as possible.
She rattled off his insults directed at immigrants and others and again raised his treatment of women, saying: “Donald thinks belittling women makes him bigger. He goes after their dignity, their self-worth, and I don’t think there’s a woman anywhere who doesn’t know what that feels like.”
Another effective punch was her response to Trump saying she’d been around politics long enough to have already done much of what he’s pledging to do now. She contrasted his achievements with hers, which could have come across as arrogant but instead managed to hit the right tone.
But, of course, Clinton has been lucky throughout in her opponent — he keeps straying off message and digging himself into self-made controversies, the most recent of which was his refusal to say he would support the outcome of the election.
At this point, he either trails her or is running neck-and- neck in every key battleground state.
He is also being seriously outplayed by the Clinton campaign when it comes to get-out-the-vote efforts. He has 207 field offices nationwide, compared to 489 for Clinton. She and her allies have roughly twice as much cash as does Trump.
So she clearly has the cash and the ground game well in hand as she heads to the finish line. Her debate performance, too, may now put a sprint in her step— the CNN/ORC polls immediately after each of the three debates made it a hat trick for her.