A week and a half after Politico first reported on sexual harassment allegations made against Herman Cain in the 1990s, the story has grown to include four accusers, two of whom have publicly identified themselves and one of whom has given details of the alleged harassment.

With each new accuser and bit of information that comes out, the evidence of some level of wrongdoing on Cain's part grows that much stronger, but there is no definitive proof, and Cain has vehemently denied all of the allegations.

On Tuesday, in a press conference in Scottsdale, Ariz., he repeated his denials and mocked the critics who predict he will have to drop out of the presidential race, saying, It ain't going to happen. He seems confident that, despite the steady drip of new accusers and salacious details, he can regain his footing and win the Republican nomination. But can he?

Down the Poll Hole

Even as late as last week, amid criticism of Cain's initial, fumbling responses to the Politico story, a recovery seemed possible. A Washington Post-ABC News poll conducted in the first four days of the scandal found that 70 percent of likely Republican voters said the allegations would not affect their vote.

There is obviously a lag effect between what the public is processing and what the poll numbers have been indicating, Jamie Chandler, a political science professor at Hunter College in New York City, told the International Business Times. But from subsequent polls, it seems the allegations are beginning to take a toll.

According to a Reuters-Ipsos poll released on Sunday, Cain's favorability rating among Republicans fell from 66 percent to 57 percent in one week. Ipsos noted that the poll was conducted online, meaning typical margins of error do not apply, but the 9 percent drop was the first indication that the campaign might be in trouble, and traditional telephone polls have begun to corroborate that.

A Poll Position survey of 1,386 registered voters, which was conducted immediately after Cain's press conference on Tuesday, found that only 35 percent believed Cain when he said the allegations against him were completely fabricated. A plurality, 43 percent, did not believe him, and 22 percent had no opinion, with a margin of error of plus or minus 3 percentage points.

There was a dramatic difference of opinion between Republicans and Democrats, with Republicans believing Cain's denials by a large margin, 54 percent to 24 percent, and Democrats rejecting his denials by an even larger margin: 63 percent to 15 percent. That was a piece of good news for Cain, since he couldn't have expected to get much Democratic support anyway.

But Cain fared poorly among the all-important independent voters, of whom 34 percent believed the charges were fabricated and 45 percent did not.

In the general electorate, skepticism of his denials crossed all racial and ethnic lines. Pluralities of white, black, Hispanic and other voters all rejected the idea that the allegations were fabricated, which deals a blow to Cain's efforts to characterize the backlash against him as a racially motivated smear campaign.

Opinions did differ along gender lines. Men were more likely to say the allegations were fabricated, 43 percent to 38 percent, while women were more likely to say the allegations were legitimate, 48 percent to 27 percent.

The Pursuit of Independents

The loss of independent voters poses the biggest threat to Cain's campaign. Most Republicans are inclined to support him and most Democrats are inclined to oppose him regardless of what he says or does, but independent support is important in the primaries and crucial in the general election.

The most partisan supporters are not going to turn away from him in droves, Chandler said. But when you move toward the middle of the party, they're going to go away -- and he was starting to capture those people.

Cain has dominated the conservative and Tea Party markets since late September, when the Rick Perry train crashed, and he will probably continue to dominate those markets. But Mitt Romney has polled better among moderate Republicans and Republican-leaning independents, and Cain knew from the start that he would have to poach some of those voters in order to break his tie with Romney.

Before the harassment scandal broke, that seemed possible. It is not impossible now, but it is a much taller order.

Even some conservatives are beginning to question Cain's honesty, calling on him to respond more specifically now that his accusers have made more specific allegations.

Penny Nance, the president of the conservative group Concerned Women for America, called on Cain to respond to the Politico story when it was first published on Oct. 30, and once he did, she said she was satisfied with his denial. Barring other information coming to light, I think he has gone a long way to put it to rest, she told Politico on Nov. 1.

But other information did come to light when Sharon Bialek -- a former employee of the National Restaurant Association's Education Foundation -- held her press conference on Monday and accused Cain of trying to grope her in 1997, and Nance urged Cain to respond accordingly.

Unlike anonymous allegations, Ms. Bialek appeared credible, and I was very disturbed by her characterization of what happened, Nance said. Whoever Republican primary voters choose as president should be a man or woman of good moral character. We said when Bill Clinton was president that character counts, and we still believe that.

When asked on Tuesday whether he thought it was fair for voters and pundits to put his character under the microscope along with his policies, Cain said it was perfectly appropriate so long as they evaluated his character based on facts, not unsubstantiated allegations. But Nance's remarks indicate that some voters, even conservatives, are starting to question whether the allegations really are unsubstantiated.

If Cain no longer has conservatives in his back pocket, that is a potentially serious development, but unlike independent support, conservative support is eminently salvageable. Conservatives may have begun to doubt him, but they will still be inclined to take him at his word if he does refine his response, and they are likely to stand by him even if there does turn out to be some truth to the harassment allegations.

He Said, She Said

If independent voters are the most important wild card, where does that leave Cain?

What makes the outcome of the scandal difficult to predict is that it has become a classic he-said-she-said affair, with the two sides firmly entrenched in contradictory stories.

Two former National Restaurant Association employees received five-figure severance packages after accusing then-CEO Cain of sexual harassment, and two more women have come out to say that he sexually harassed them as well. But Cain says he has never acted inappropriately with anyone, period.

Cain says that the only incident he can recall that could possibly have been construed as sexual harassment was one in which he gestured to his chin and told a female restaurant association employee that she was the same height as his wife. But the employee, Karen Kraushaar, who now works as a spokeswoman for the inspector general of the Internal Revenue Service, called that innocuous and said it was not part of her complaint, which was centered on multiple other incidents that she did not describe.

Sharon Bialek says that Cain reached up her skirt, tried to touch her genitals and pulled her head toward his crotch after she asked him for help finding a new job with the restaurant association. But Cain said at a press conference on Tuesday that he had never seen Bialek in his life and didn't recognize her name. Bialek responded by calling Cain a pathological liar.

When the allegations can be neither proven nor disproven, it is impossible to move the discussion beyond the realm of he-said-she-said.

There are no photos, videos or forensic evidence. There is one eyewitness account from a Republican political consultant, Chris Wilson, who says he saw Cain acting inappropriately toward a female employee at a company dinner in Crystal City, Va., but there is no way to confirm his account, just as there is no way to confirm Bialek's, Kraushaar's or Cain's.

The closest we can come to proof is sworn statements made under penalty of perjury. Bialek's boyfriend at the time of the alleged incident and another friend of hers have both signed affidavits that she told them back in 1997 that Cain had acted inappropriately toward her -- long before she knew that he would be running for president or that the allegations would become public.

Politico also reported that it reviewed documentation of the settlements from the National Restaurant Association. If those documents were released, they could confirm whether Cain is telling the truth when he says that the restaurant association concluded that the complaints were baseless.

Republican strategist Karl Rove, who was a top adviser to President George W. Bush, said Cain should do just that.

The way to get it behind him is for the National Restaurant Association to take those reports which he says exonerate him and get the reports out, Rove said, according to Politico. Lay out those reports, redact the names of the women, give them some privacy -- he says those reports will confirm he did nothing wrong. Let's hope they do.

Cain has not done so, and that has provided ammunition to critics who say that if he really had nothing to hide, he would ask the restaurant association to release the documents right away to prove his innocence.

We have heard everything from liberal media bias to racism to 'my opposition did it,' but until Cain says what happened, when it happened, where it happened, why it happened and with whom it happened, this story is not going away, Ronn Torossian, the CEO of 5W Public Relations, told IBTimes last Friday. The accusations may indeed be false, but if agreements were signed, something happened, even if it wasn't harassment.

What's Next?

So what will become of Cain now? Will he manage to push the scandal off his shoulders and surpass Romney, or at least make a good run for the nomination? Or will he finally be forced to admit to the allegations, like other politicians -- Anthony Weiner; Bill Clinton -- who fiercely denied sexual impropriety only to admit to it later?

Chandler, the Hunter College professor, doesn't think Cain will acknowledge sexually harassing anybody, even if he did, for the simple reason that there is no proof.

Weiner, a former U.S. representative from New York, tried valiantly to deny in June that he had sent lewd tweets or texts, but as conservative blogger Andrew Breitbart released a series of increasingly incriminating photographs, Weiner had no choice but to admit it.

Similarly, former President Bill Clinton could only deny his affair with Monica Lewinsky for so long when Congress was on his tail, and armed with forensic evidence -- Lewinsky's infamous stained dress -- to boot.

Cain's case is different. Even if he did sexually harass Bialek, Kraushaar and/or the other two accusers, the public may never know.

The lack of proof does not necessarily mean that his campaign will survive, because that will be determined by public perception, not hard facts. What it does mean is that, if he does drop out of the race, he probably won't attribute it to the harassment scandal.

The more likely scenario is that he would drop out of the race and not really address the charges, Chandler said. It's more plausible for him to say, 'I'm dropping out of the race because the Democratic machine has made it impossible to continue,' or he'll do it 'in the best interest of the party.'

It is obviously possible for politicians to survive embarrassing revelations -- just look at Newt Gingrich's extramarital affairs and Mitt Romney's hiring of illegal immigrants -- but survival is a product of a good public-relations strategy. Cain never really developed that, because this is his first national campaign and he was considered a third-tier candidate until late September. As a result, he has been slow to hit his stride in responding to the allegations.

In Romney's case, the various allegations made against him haven't stuck because his campaign organization has been able to scuttle them in one way or another, Chandler said.

But Cain's very public, very brash denials have courted media attention, which has tended to be negative, and spurred his accusers to take a more vehement stance. There is even talk now of the four accusers holding a joint press conference to tell their side of the story, and the extended publicity is much more devastating than the allegations themselves.

These charges, in and of themselves, aren't enough to do in a candidate nowadays, Brian Kirwin, a political consultant for Rourk Public Relations, told IBTimes last Friday, when the allegations were still anonymous and ill-defined. The issue of harassment is almost superseded by the issue of his personal honesty. If a first-person, detailed account comes out, even if it's a he-said-she-said -- if that puts a big question mark on Herman Cain's honesty, he's finished. Republicans have very little tolerance for that, especially in primaries.