LAS VEGAS (AFP) - Mr Donald Trump will aim to dump his losing political hand on Wednesday (Oct 19) in his third and final presidential debate with Mrs Hillary Clinton, as polls show the Democrat has widened her lead over the provocative billionaire.
With just 20 days before Americans cast ballots on Nov 8, the two candidates will face off at the University of Nevada, Las Vegas at 6pm (9am on Thursday, Singapore time) in what is sure to be a 90-minute slugfest watched by millions.
The Republican nominee, 70, is looking to bounce back from allegations made by several women of unwanted sexual advances, which came on the heels of the release of a 2005 video in which he made crass remarks about women.
"This is our final shot, folks," Mr Trump, who has in recent days made multiple unsubstantiated allegations that the election will be "rigged", told supporters on Tuesday in Colorado.
In recent weeks, polls have shown Mrs Clinton, 68, pulling ahead of Mr Trump both on the national level and in key battleground states. She leads by more than six points in an average of national polls compiled by RealClearPolitics.
Women especially have thrown their support to Mrs Clinton - the difference now stands at 52 to 38 per cent, according to a survey by Quinnipiac University.
Team Trump set the tone ahead of the political battle, with campaign CEO Steve Bannon promising that their debate invitation to President Barack Obama's Trump-supporting half-brother Malik was "just an appetiser".
The Manhattan real estate mogul has invited other guests who "expose Bill and Hillary's sordid past", Mr Bannon told CNN, referring to Mrs Clinton and her husband, the former president.
The pro-Trump Breitbart website also published allegations by a former television reporter that Mr Clinton sexually assaulted her three times while serving as governor of Arkansas.
Mr Clinton's spokesman Brian Fallon said he "wouldn't be surprised" if Mr Trump raised those claims during the debate, adding that the billionaire's scorched earth strategy could backfire.
"If he brings this approach to the debate stage tonight, it will be his loss," he told MSNBC.
Moderated by Fox News journalist Chris Wallace, the event is expected to draw a television audience of more than 50 million, as well as many viewers online.
The candidates will be asked about the economy, immigration, the Supreme Court, foreign flashpoints and their fitness to be president.
But if the past two debates were any guide, the duel could quickly descend into highly personal attacks, pushing substantive policy issues to the side.
Mrs Clinton, a former secretary of state and senator, has kept a low profile in recent days, shutting herself in with aides to prepare for the onslaught.
She "should do what she did in the two first debates which was largely remain calm, deflect criticism and attacks and let Donald Trump continue to self-destruct", said Mr John Hudak, a senior fellow at the Brookings Institution.
"If your opponent's ship is sinking, you don't throw them a life preserver," he said.
Mr Trump undoubtedly will draw on the lessons of the past two head-to-head battles, and sharpen his attacks on Mrs Clinton over Syria and Libya.
The 2012 Islamic militant attack on the US mission in the Libyan city of Benghazi remains a burning issue among Republicans, who hold her partially responsible for the deaths of four Americans, including the ambassador.
Mr Trump has invited Ms Patricia Smith, the mother of an American killed in the attack, to attend the debate, campaign manager Kellyanne Conway said.
But Ms Conway advised Mr Trump to "focus" on the issues, and come out strong against Mrs Clinton herself.
She is "a known liar", Ms Conway told MSNBC. "She's lied to Congress. She's lied to the FBI. She lied to the Benghazi families. She lies and it's always for political gain."
Mr Trump also is likely to hammer Mrs Clinton over recent revelations from e-mails hacked from her campaign staff and released by WikiLeaks that exposed her closed-door speeches to Wall Street and showed her flip-flops on trade deals.
Mr Trump predicts an electoral surprise, or "new Brexit", when Americans vote next month.
The White House is increasingly concerned that Mr Trump and his supporters will not recognise the election's outcome, plunging the country into a political crisis.
In a scorching rebuke, Mr Obama told Mr Trump on Tuesday to "stop whining" and go make his case to voters.
"I have never seen in my lifetime or in modern political history any presidential candidate trying to discredit the elections and the election process before votes have even taken place. It's unprecedented," the President said.