In an extraordinary clash that took an already bitter presidential contest down into the gutter, Donald Trump on Friday urged voters to check out an alleged "sex tape" of a former Miss Universe who backs Hillary Clinton, provoking the Democrat to fire back that he is "unhinged."
In a pre-dawn tweet-storm of a sort guaranteed to grab attention, the Republican accused Clinton of helping Alicia Machado get US citizenship in order to exploit her during their presidential debate this week.
The Venezuela-born Machado, who claims the billionaire bullied her mercilessly after she won the Trump-owned beauty pageant in 1996, has since shot to public attention.
"Did Crooked Hillary help disgusting (check out sex tape and past) Alicia M become a U.S. citizen so she could use her in the debate?" Trump tweeted.
Clinton lashed out on the debate stage at Trump's history of abusive remarks about women, and assailed her rival for publicly humiliating Machado after she gained weight following her beauty pageant win.
Machado accuses Trump of verbally abusing her, calling her "Miss Piggy" over her weight and "Miss Housekeeping," apparently because she is Latina.
"Using Alicia M in the debate as a paragon of virtue just shows that Crooked Hillary suffers from BAD JUDGEMENT! Hillary was set up by a con," Trump tweeted Friday.
The Democrat lost little time in responding, tweeting that Trump's virulent stream of attacks bolstered her argument that he lacks the steadiness or temperament to be president.
"This is ... unhinged, even for Trump," Clinton said in her own series of pointed tweets in response to his sex tape allegation.
"What kind of man stays up all night to smear a woman with lies and conspiracy theories?" she said.
"When something gets under Donald's thin skin, he lashes out and can't let go," Clinton went on. "This is dangerous for a president."
A spokeswoman said Clinton would have more to say on the subject later in the day.
With just five weeks left in a close and increasingly vitriolic race, the issue might help Clinton among both women and Hispanic voters, who could make the difference in a vital battleground state like Florida, where the Democrat was campaigning Friday.
Trump has at time seemed to issue his strongest provocations as a way to deflect media attention -- in this case from the widespread sense that he fared poorly in Monday's debate. He has also hinted at plans to attack Clinton over her husband Bill's past infidelity.
But he has also seemed unable, at times, to let any criticism go unanswered. Indeed, observers saw Clinton's mention of Machado as a plain attempt to bait Trump -- and one he was unable to resist.
"It is not apparent to us why he simply can't stop attacking her," a Clinton spokeswoman, Jennifer Palmieri, told reporters Friday in Florida.
She said the Democratic candidate would "stand up and defend" Machado against his "very demeaning" remarks, adding that Trump needed to "stop attacking her and apologize."
Palmieri also said that neither her boss nor anyone in the campaign had helped Machado get citizenship.
According to the fact-checking website Snopes, Trump's sex tape allegation appears to refer to Machado's appearance on a reality TV show in which she is shown in bed with another participant, under the covers.
Machado was also pictured in Playboy magazine. But a pornographic video circulated in recent years purporting to star the former Miss Universe was debunked as a fake.
Trump, addressing his nearly 12 million Twitter followers, charged that Machado had "duped" the Clinton campaign.
"Wow, Crooked Hillary was duped and used by my worst Miss U. Hillary floated her as an "angel" without checking her past, which is terrible!" he wrote.
The former beauty queen has seen her profile raised considerably by the controversy.
Trump's brutal criticism of Machado's weight included TV images repeatedly re-broadcast this week showing her being put through the paces of a weight-loss exercise regimen in front of television cameras.
During a news conference call this week, speaking in a mix of Spanish and English, Machado heaped contempt on Trump for his past mistreatment.
"He doesn't remember me, he doesn't remember many things that he did to me, or that he told me," Machado told reporters.
"It was evident that maybe he doesn't remember an 18-year-old girl, whom he insulted and offended and mistreated a thousand times. But I'll always remember," she said.